Like Gregg said, Michigan law can be interpreted to mean anything over 5000 must scale. One statute says one thing, another statute says something else. I've never stopped at a Michigan scale.
Kentucky does not require it, I promise you. I'm also a resident of Kentucky, and after reading here on EO that Kentucky required it, a surprise to me at the time, I decided to check it out and had it confirmed both verbally and in writing from the State Police. Kentucky Revised Statutes use the verbatim wording of the FMCSA definition of "commercial motor vehicle".
Alabama law, as of June 27, 2006, does not require logging or scaling of any vehicle that is outside the scope of the "federal motor carrier safety regulations as prescribed by the U.S. Department of Transportation, 49 C.F.R. Part 107, Parts 171-180, Parts 382-384, and Parts 390-399" {Alabama Vehicle Code
Section 32-9A-2}. That means vans don't have to log and scale in Alabama unless you are a Commercial Motor Vehicle in the eyes of the FMCSA.
Wyoming requires all deliveries into the state, whether you are a commercial vehicle or not, to stop at the scales. Trucks, vans, station wagons, cars, anyone delivering something into the state. If you are just passing through you do not have to stop. The first time I entered Wyoming, on the way to California, I stopped because the sign read like it meant I should. They said no, only if you are delivering into Wyoming. I have delivered into Wyoming 3 times, all 3 times I have stopped at the scales. All 3 times they checked out my paperwork, and all 3 times thanked me for stopping (they're very nice in Wyoming), and all 3 times they said with vans it's really just about raw food products and HAZMAT and that if I wasn't carrying something like that, I really didn't have to stop. But I'll continue to stop there if I'm delivering into the state.
No other states require vans to stop. Of course, in all states, if you are placarded, then you are a commercial vehicle, and commercial vehicles must stop at all scales. Florida and California have Agriculture Stops, and of course the Border Patrol stops in Texas and Arizona and California.