> Seems to me that if we're going to have a "law" we need to think about it more carefully. 
Don't think we can have a law, at least not easilly. Too many variables.

> Second, one would expect that the more the van costs to start, the less the repairs should be after that, since presumably the 
> cheap vans are those that need more investment.�
IMHO, this presumption is incorrect. I've seen PLENTY of $$$ Westys that showed signs of needing significant work in the future (hairline cracks on the seams, old/swelling hoses, on an on).

> Third, we need to control for where it was bought (east coast vans are more than west coast, due to lack of supply)
West coast vans seem to cost more than comparable east coast (mid Atlantic, in my case). They are harder to find here -- and not cheap -- but it's rare to see them at CA prices.

Rather than a 'law', I favor having a general guideline for initial costs, repairs based on age, and ongoing maintenance costs. That should give new buyers a better idea of what's coming!

john