Dave,
There is concern by some of the collector folks here, but an unfortunate amount feel like it's just "somebody else's problem, at least for now".
But in fact, at my appeal, another Madison fellow testified that DOT had tried to keep him from registering his '70 Leland Mini just a few years earlier (also a FMVSS-exempted import vehicle). After he initiated an appeal, DOT agreed to register him. after all. I'd think that would be considered a collector car, even if it's not a Ford or a Chevy? He sure considers himself an enthusiast.
DOT has been trying to outlaw all kinds of "fringe" vehicles, apparently, for some time. It seems that they've been cautious enough to not say much. IIRC, during a DOT hearing in July, 2009, they assured collector car enthusiasts that their cars would not be targeted. Then again, in a Nov. 2007 Wis. State Journal article, DOT's Linda Lewis said it was because of the VIN numbers didn't indicate FMVSS-compliance. She said "It really wasn't a change. It was really just to (do) what...we should have been doing." How many pre-'68 vehicles have VIN numbers which show FMVSS-compliance? Zero.
Something changed, and it wasn't Wisconsin's laws. It was only DOT trying out a new interpretation.
And yeah, we've tried to talk reason to DOT. It hasn't worked. That's what got my Senator so upset that he introduced his bill to force DOT to register HMVs.