Lets keep it clear. First, I have nothing against trying it and fully understand the feelings involved (and the cash). Unfortunately, that is not relevant here.
For those who bid on a HMMVV, paid and signed the papers,
1) was it stated clearly that you bought the vehicle with a limited off-road use only?
2) Those who tried, when talking to the DMV, did you know that the bill of sale clearly said or would say "sold under off-road only conditions"?
3) If yes did you tell the DMV people clearly when talking with them that most if not all of these vehicles came with the "sold under off-road only conditions"?
If yes on two or three of the questions above, you took a gamble intended to go against a legal contract before signing it. Legally (in a perfect world), any case in court should be kicked out very quickly against you ( I am not completely unfamiliar with laws and court cases at least here in Europe where we love to go to court on principle or for the h**l of it).
If the sellers were not clear up front with the limited use only, then you have a case against the seller ... maybe, but not against any DMV. Dito if somebody did the trick before you and sold you a titled but "limited use only" HMMVV without telling you, you have a case against the seller but not against the DMV.
If you just mentioned to the DMV you have this nice vehicle that currently is not street legal but you would like to make it street legal without mentioning the signed contract conditions, you actually might be in problems with the intent to mislead the DMV. Maybe that is going a bit far but as DMV officer, if I got involved and this little sentence has been left out or at least not stated very clearly, I would be upset about the applicant and it would go against you in a court.
Again, and as said many times before here, for the law it is completely irrelevant whether or not the vehicle is actually road worthy or not, and whether or not some other people managed to get a paper-folded boat road worthy and titled so why not you.
The first question always will be: did you sign a paper stating the off-road-only status? If yes, bad luck, go home. If no, you might have a case against the seller or the DMV, but it will cost you waaaayyyyyy more than the $ 30 000 you have in it now. It will cost you real hard cash in legal costs, in-kind in the form of the endless hours and days you will spend on it, and in health and joy of life for you, your family, and your other close ones. You will get bitter and grey hairs before it is over.
Yes, sometimes life kicks you in the teeth you just had repaired for a fortune. I can fully understand those feelings, been there over and over again.
In the eyes of the NHTSA, any off road only branding is absolutely meaningless because there is no way for the seller to hold the buyer to that standard:
https://isearch.nhtsa.gov/gm/94/nht94-1.78.html
If we conclude that a vehicle is manufactured primarily for on road use, it is a "motor vehicle," notwithstanding the fact that it may be sold "on the basis they would only be used for off road purposes." We see no way in which a seller can bind a purchaser to such use, and, certainly, such a restriction would not be binding on subsequent owners of the vehicle.
Also stated in that letter, as you can see at the link, military vehicles are not required to conform to FMVSS:
However, NHTSA excuses vehicles from compliance with the FMVSS if they have been manufactured in accordance with contractual specifications of the armed forc es of the United States (49 CFR 571.7(a)). Furthermore, because the Safety Act does not regulate sales of vehicles to owners subsequent to the original one, the U.S. armed forces may sell military vehicles to the public at the end of their useful milita ry life without having to bring them into conformity with the FMVSS
Additionally, as Maverick posted there are letters from the NHTSA to AMG confirming, not once but twice, that the HMMWV is a "motor vehicle" in the eyes of the NHTSA:
here and
here.
So, anything beyond the fact that:
1) The HMMWV is a "motor vehicle" designed to operate primarily on roadways,
2) The HMMWV is exempt from FMVSS because it is a former military vehicle, and
3) The off road branding is meaningless to the NHTSA,
is a misinterpretation. Not to say that states aren't free to misinterpret or incorrectly rule and, in which case, they will need to be corrected through either legislation (preferably) or judicial action.
The law is on HMMWV owners' side but sometimes, government needs to be reminded that it too must follow the law.
ETA: The contractual obligations of the sale have zero bearing on compliance with state/federal law regarding the registration and operation of the vehicle on the road. As I mentioned in my last post, that is a matter of civil law. If GP really wanted to, I suppose they could bring suit against people for breach of contract for registering them for on road use but, a) there's no guarantee they'd win and b) even if they won, it still would have no bearing on whether the registrant was in compliance with local motor vehicle law.
GP making the buyer sign an agreement that the buyer will only operate the truck off road only carries the same weight as if GP made the buyer sign an agreement that they will only drive the truck while wearing a red squeaky nose and clown shoes. Can they do it, sure. If they buyer doesn't, would they be in breach of contract, possibly. Would the buyer be in violation of local motor vehicle law, almost certainly not.