This has been a well traveled line of thinking but in the end the result is the same. Unless you want a visit from the IRS forget about depreciating your kit and tools. The only feasible way I can see them being depreciable is if you own a education center and are building the aircraft as part of an educational program that people pay for.
This would have to be a legit business with numerous students, not just you and your significant other

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A flying RV could be depreciated if used in a commercial operation. I'm not one hundred percent sure on this though.
As far as I know, those are your options. Oh, lest I forget, if you own a buisness that requires you to travel you can depreciate all associated costs of that travel.
You're playing with fire if you don't have a solid reason to deduct. Boats, planes and RV's (recreational vehicles) are all red flags to the IRS.