For what it is worth:
The regulations and requirements for Section 179 are related to those for depreciation (Section 167 and 168), and are tied to Section 162, ordinary and necessary business expenses. Section 179 simply allows a business person to accelerate depreciation to the point of deducting most or all of the cost of a business asset in the year of purchase (or year placed in service if not placed in business service in the year of purchase), subject to several limitations.
Assets don't qualify as business assets simply because of their physical nature, or because the person who owns them is in a business. To qualify as a deduction, an asset has to be BOTH ordinary within the context of the business you are in, and necessary to the conduct of that business (Section 162). I could buy an 8 ton dump truck, but if I don't use it for business, or if it is not ordinary and necessary for the business I am in, I can't take a deduction for its purchase or operation.
An EarthRoamer is not likely to qualify as ordinary to most business, and just about as unlikely to qualify as necessary unless you are in the business of exploring remote parts of the earth, or unless the usefulness of the ER falls clearly within the parameters of your business operation. I would expect the ER to be seen and treated similarly to a motor home or other RV. If it has sleeping, cooking, and eating facilities built in, it will first be seen as an RV, not as a business tool. If you need an RV to conduct your business, you have a chance of prevailing. If the RV features don't appreciably detract from the business usefulness, you have a change of prevailing. Because of the cost involved, your deduction is likely to be reviewed for several reasons outside the scope of this post.
Mention was made that the ER could qualify as a mobile office. Perhaps, but it would have to be an argument made if challenged, as the ER is not set up as an office, but as a camper. The ER's foremost function is for off-road expedition travel, not mere mobility, and this fact is not only widely known but readily determinable from the internet. If, on the other hand, you have an ER which has been converted to the purpose of an office rather than as a camper, and especially if your business takes you to off road locations, you might have a good argument.
The cost of the asset is nearly always not the issue, although there are and always have been cash limits to the deduction. Just because something costs more than the 179 limit does not mean that you can't take 179; it means that the amount over the limit has to be depreciated under MACRS, and vehicles are generally 5 year property IIRC.
Other rules apply. For example, because the ER is a motor vehicle (and one under 6,000 GVWR to boot) it is listed property subject to SUV and other limitations. To deduct any of the cost of listed property other than (generally) the cost of operation, you have to use the asset more than 50% for business, and you have to be able to prove it. If you don't use it more than 50% for business, you might write off the cost of gas for business trips or a pro-rated portion of maintenance, but the balance of associated costs would be limited or not available as a deduction. This same >50% rules applies to Section 179 but is more critical, so if the goal is to expense the full cost the of ER in year placed in service, expect to use the ER more than 50% for business purposes to qualify for 179.
Mention was made of Scott's ongoing conversion. I don't presume to know Scott's business and certainly am not familiar with his tax matters, but as a retired member of Office of Chief Counsel IRS, my guess would be that if Scott's business acquires the ER in a manner that qualifies for depreciation, his use of that vehicle would come about as close to actual business use of the ER in its original build state as I could imagine. For most anyone else using it for, say, a mobile office as a real estate agent, construction company, or some such, I would not be surprised to see the deduction challenged, and the burden of proof is always on the owner, not the IRS, and the area of law is not exactly black and white. Any personal use of the vehicle, for camping or exploration or commuting or whatever, will have to be carefully accounted for with contemporaneous records, and such use will detract from the potential for business deduction.
Personally, I would view the press release as a marketing tool. The statements made by ER are not incorrect in themselves, but are also not what I would see as tax advice. I have seen a lot of these kinds of ads. As with any asset, the eligibility of the purchaser to qualify for a tax deduction has to be determined by the purchaser. No one who sells assets can claim that you can qualify for a tax deduction simply by purchasing their product, and all of the manufacturers who make tax-related marketing moves will disclaim expertise in tax if they have a conscience. Nothing about the change in the tax law suddenly made the ER qualify for a deduction it did not qualify for previously. The change in the law just pushed the deduction limit up for vehicles under 6,000 pounds GVWR with the intention of attracting new purchases of a serious nature in order to "stimulate the economy." It is the amount of deduction that changed, not eligibility for a deduction. That the cost of a vehicle plus the ER conversion now falls below instead of well above the 179 limit is the only change I can see, and pointing this out to a potential market is, in my opinion, simply marketing strategy. There is nothing wrong in this and no harm in it, and none intended, but if one is not familiar with the tax laws, one might think if they don't purchase an ER right away, they might miss out on something, and that I believe is not true. Even if the 179 limit goes back down, or even if 179 is repealed, if the asset qualifies as a business deduction it will still be deductible.
Timing is mentioned in the e-mail. To understand why timing is important you have to understand "placed in service." To be placed in service, the asset must be in a condition of readiness that allows its intended use. That means, for the ER, the vehicle would have to be delivered in hand not merely ordered and/or paid for, and if not configured in such a way that it can be used as intended for your business (suitable to use as an office for example) it would also have to be further converted to your particular use before it could be placed in service. If you believe the ER will qualify for business use as built, it would be placed in service when it is delivered to you, as long as you actually begin to use it for business more or less when it is delivered. (There are special rules for delayed service which are way beyond the scope of my recollection). Because of the delay between ordering and delivery, ER mentions the timing issue.
My best advice, even though not solicited, would be for anyone thinking about deducting the cost of the ER or any similar RV, contact a tax professional and talk it through carefully. If you think that taking a deduction might be pushing the envelop, don't be annoyed if your return is audited. Instead, be prepared to show full documentation on the use of the vehicle for business and for any incidental personal uses.
[edit] One or two further notes as things occur to me: 1) qualification for 179 has to continue throughout the depreciable life of the asset, so if you use the asset more than 50% for business in the first year and otherwise qualify, but in the second, third, fourth or fifth year you no longer qualify, you have to recapture some of the cost expensed under 179. This is a complex area. 2) To qualify for 179, a vehicle has to be new, not converted from personal use, and it can be argued that a converted Jeep is still a converted Jeep (or whatever you build on). Thus, if you do an ER conversion on a vehicle that was originally a personal use vehicle, arguably the ER conversion might qualify for 179 but the cost of the vehicle would not. However, from the IRS' perspective, expect an argument that a vehicle converted from personal use to business use ER conversion will not qualify for 179 and would have to be depreciated normally, with the basis for depreciation of the vehicle converted to be determined at the lesser of cost or market value at the time of conversion. Also a complicated area.
