It also comes down to the basics of supply and demand. AD suburbans are getting harder and harder to find with each passing day. Those that have them for sale can ask more becuase your options are limited. It's really no different than anything else.
With that said keep the faith and keep looking. In July, I found a 53 Suburban which I understand were the fewest Suburban (by year) produced. I paid a fair price and it was 95% complete with little rust. Cheaper than what I have seen a lot of them go for.
Marc
