If you have the will, there is a way to restore legitimacy. Stolen/impounded vehicles/campers are often sold through police auctions, used as bait vehicles, or other clandestine law enforcement operations if the value is high enough. Customs and DEA are the same way. Even our government knows better than to crush up a $250,000 Ferrari just because Scarface owned it before he was killed in a drug deal gone bad.
The real question only YOU can answer is, "Is it worth your time to do it?" (make it legal again) Without having a specific unit in mind, my gut feel (guess) would be that the initial purchase price would have to be about 10% of the legitimate legal value if we're talking units over 5 figures in value when legit. I'm sure there are great deals out there if you have the knowledge, time, space, tools, and, . . . . patience to deal with what comes next. If not, move on.
Chum lee