We talked about this today at lunch... Installing GPS tracking devices on all automobiles starting in 2010 would be a great way for all auto manufacturers to sell their current inventory! Just think... If you don't want the device in your car, you buy an '09 or older model... Used cars start looking more attractive to consumers as well. Of course all of this was said in jest, but it just might work.
They've been talking about that here too. We were talking about it at work the other day, and someone said all they would have to do for administration is require an odometer reading when you renew your plates every year or transfer the title to someone else.
For Michigan, it would be another blow to the economy and crumbling roads. At least the gas tax keeps the money here where the vehicles are driven, no matter who owns them. A good portion of all vehicles on the road around here belong to another state, and most of those are recklessly driven gas guzzlers. So with the mileage tax they can come beat up our roads and their home state gets the money. But it is another way to relieve tourists from any responsibilty for their actions, which anyone in power is all for.
__________________
Winter daily driver, parked most days right now