I really like the idea, as well as your trailer selections. I’d stay away from the teardrop concept to start as there are quite a few on the market, and people will want it 6” wide or 6” taller, etc. They are also harder to build to a lower price point. I’m not sure what business experience you have, but I see your target audience being 25-50, middle income, DIY types that own a drill but are not skilled fabricators. These people will be content to bolt things on or build a wood shelf, but probably not doing heavy electrical wiring or using a hole saw through the metal skin.
I agree with having a base model to keep costs down, but I think it’s a mistake to not offer a ton of individual options, especially with a direct sales model. It’s a different industry, but look at
http://www.customgheenoe.com/price-list/lo-tide-25/ for an idea of an options list.
This is a really stout option for an affordable axle, and will allow you to run longer leaf springs and taller tires while keeping the COG down.
https://www.southwestwheel.com/c-1249-3500-lbs-4-drop-dexter-trailer-axles.aspx They also come with brake backing plates so those who want brakes can add them. I pull a 2,500 lb (loaded) cargo trailer with a 1/2 ton Suburban and have felt no need for brakes or issues stopping.
For the M100 style trailer, I agree that a $2,000 price point with a lid would sell well. It would be nice to have gas shocks and front hinges that can be easily removed to haul taller items like mountain bikes. Probably not many options on this model as there’s not much to be done besides a tongue box, spare tire, and load bars. A longer removable tongue to accommodate kayaks would also be nice.
For the Scout type trailer, I would offer options like a propane tank holder and line, 12v electrical package (basically just a deep cycle battery, charger, fuse panel, and inverter) to allow easy additions.
For the enclosed trailer, I’d look at a 6x12 V-nose that’s tall enough to stand up in. I paid $2,150 for mine brand new, but it’s a construction model. A reasonable profit at a $5k price point with insulation, better tires, RV door and window, and nicer interior finishing/panels should be achievable. I would definitely offer an electrical package on this model, and at least install one of these power ports standard.
https://www.etrailer.com/Accessorie...mbO2lt3vEKqEnkKQZE2rOaIcHuA18td4aAp1IEALw_wcB
Options like roll up screen doors, awnings, E-Track to support a bed frame, hammock hooks, etc, would be popular. Maybe a small countertop/cabinet in the V-nose section as well. This model would be really popular for people with kids and toys, especially if it can be reasonably well configured for $8,500ish.