Some more thoughts on cost. (this is an excerpt of a post I made on RV.net in a thread related to building your own Earthroamer)
It takes a tremendous investment of time and a significant investment of dollars to build one of these things on a custom / one-off / bespoke basis in a quality manner.
For instance, I worked on this full time, usually 12-14 hours a day minimum from 15 September 2006 to 4 June 2007. That's 263 days. My wife thinks I took at most 20 days off during that span, so that's a net of 243 days. That day count does not include the research and design work that started three days after she walked into my office and told me she couldn't go out by sailboat in early January. (The three days was a period of mourning, wailing and knashing of teeth, not necessarily in that order.)
I couldn't begin to estimate that total investment of time, but I was on it pretty much full time, 6-8 hours a day, from mid-January until we left for the proof of concept camper rental 2 July 2006. We were on that test for six weeks to see if this concept was viable for us. Starting in mid-August we were on the road dispersing our worldy goods (a bit like the reading of your will while living experience - very cool) driving all over the U.S., but I still worked on design and research every night while were on the road. Figure at least 20-25 hours a week. That lasted until 15 September.
So, timewise, I was on this full-time, plus overtime, for about 1.5 years, with very, very little time off, from the point the sailboat dream died to the point this rig rolled out. It's 505 days from 15 January 2006 to 4 June 2007. I estimate I worked on this 400-420 of those days.
How do you value that time? I don't know. I knew nothing, zero, zilch, nada about 4x4s, expedition vehicles, RVs, campers, etc. when I started this, so you can't value my time much over minimum wage at that point. By the end I was reasonably competent, if you ignore the fact I usually did everything 2 or 3 times until I got it up to the point where it could be viewed in the context of our master artist fabrictor Mark's work.
If you take an average day of 10 hours X 410 days that gives 4,100 man hours. Just by me. If I average out at $15 or 25 per hour, then that's between 60 and 100k for my time. If you think the design and assembly work was valued more like typical shop rates then that would be more like 4100 X $80 = $328k.
That does not include subcontractors, of which Mark was the primary - probably 98% of the subcontracted work. I honestly don't know how many hours Mark had in this project. He worked on it very hard from September through the holidays, including over the holidays themselves. He had some other projects during that time too, so figure at least two man months of his time. Mark is an absolute master craftsman, an artist, at metal fabrication, so you need to have a very high rate when you start doing your back of the envelope calculations. If you figure eight weeks at 20 hours a week at $100 per hour for him thats 160 hours X $100 or $16k for fabrication. He also had an assistant, plus he farmed out the stainless steel raw water tank, the aluminum fuel tanks and the storage boxes.
So, when you think about building one of these because you think it will be less expensive than an Earthroamer or a Unicat or similar factory built solution, you may want to re-read those previous paragraphs.
How much is a year and a half of your time worth? Even if you say you are going to do everything exactly like we did so you only need to put in the nine months to build it, how much is nine months of your life worth? These are not short days. Say goodbye to your friends and family for those nine months. How much is that worth?
And what are the consequences for doing it poorly, cobbling it together? Only you can answer that.
Larry Lord, the owner of Fleet Metal Box where we had our storage boxes made, after viewing our rig told me, "I couldn't tell you how many guys have come in here over the years with big plans and big stories. Yours is the first one I've ever seen that fulfilled the vision."
It takes a very high, very sustained commitment to quality, and a tremendous investment in time, material and, yes, money, to achieve that goal.
I contend: Buy quality, buy what you can, build what you must.