When I was looking I set up a search agent on Autotrader. My criteria was a 2500 with the 8.1, 4x4, lower miles (under 125,000), and rust free. I found a handful across the country, and ended up buying one from Portland, OR.
I only kept it for about two years before we got tired of the rough ride (yes, a 2500 does ride worse than a 1500) and terrible fuel economy.
We sold it quickly as lots of people are looking for that same vehicle. Replaced it with a 2011 Yukon Denali XL. Much better ride, much better fuel economy, at least equal if not better power, and better amenities. The trade off is that it is a less capable tow vehicle, but still more than adequate for my 7000 pound boat.
If you need the 2500, and are still have trouble finding it, expand your search to include an Excursion.
