Wow, this is a good idea but would be difficult to administer. In Indiana you have the choice of regular or Military Vehicle registration. The BMV site doesn't address MV registration (called "chapter 14" here). You have to search for the code that addresses MV registration. You'll find it on the legislative pages, not BMV pages. Even on the MVPA site, our Indiana link takes you to the regular BMV site.
Even then, each office seems to have it's own interpretation of it. My local office was all mixed up on it. Persistence, patience, and a lot of calls to Indianapolis finally won over. Even now, there are aspects of the MV code that aren't properly observed due to their inability to adapt the current registration system. There are other stipulations to registering via MV that aren't written in the code. Sometime I think they are making this stuff up when I talk to them but as someone posted, some of that may be internal policies affecting their interpretations. Others I've talked to say their local offices are squared away on MVs, mine wasn't. I think because mine was the first MV they tried to register as a MV vs. regular registration.
Still, a good idea but it would take a lot of input from members of each state, someone to "fact check," distill conjecture from law, and consolidate it to an authoritative post. In the end I think most of it would be everyone sharing their experiences.