I have a question. Just giving this thread the quick once-over, I have to ask how much of the desire to regulate light trucks/CVs has anything to do with safety-- which, some folk DO push the envelop to the braking point, you know good and well that those "Tonka Trucks" are way over 10K regardless of what the door sticker says-- and how much of this is fueled by the greedy desire to eliminate competition? I'd have to say, based on what I read here and on some other threads, that greed has more than a little to do with it.
Regulating would, of course, get the violators either off the road or shaped up, one of the two. The other, hoped for by more than a few here effect, would be to make CVs in general so unprofitable that no one running them could stay in business. It's been mentioned before that CVs have profitability because they aren't regulated, if they were then they could not compete-- so it is hoped by the "regulations for all" crowd-- with dock-high trucks and would be driven out of business. With less competition, you hope to have more freight for yourself and to be able to drive prices up through supply-and-demand forces.
I have a suspicion that the powers-that-be really don't want the burden of having to regulate everybody any more than everybody is clamoring for the opportunity to be regulated. Imagine the really impossible lines if every pickup, panel van and utility vehicle had to go through every weigh station with the "Big Boys". You'd have lines that would be enormous, and many of the same folk who are calling for universal regulation now would be slapping their heads and saying "What in God's Name was I thinking" if the government ever does do what you request here.
The other thing likely to happen, in today's job market, is that a number of the folk that you so generously want to drive out of business will go on the public dole. Really, what else can they do? Then, you'll all pile down to the Soapbox, screaming and yelling about all those deadbeats who are taking tax dollars out of your pocket. Too bad, pal-- that's the breaks, and you can't drive people out of business without some of those people ending up on welfare in this economy. At least this way, they're trying to pay their own way. Maybe you might consider helping them, instead of figuring out how to drive them under. Just a thought.