I have a '71 Suburban that I put a late model split-bench seat in. I believe it's from a 2003 Silverado (with the built-in seat belts). Pretty easy to make little brackets to mount them if you have a little skill with cutting and welding. Probably any bench, or split-bench, or bucket seats with console from a full-size truck (Chevy or otherwise) can be made to fit without too much trouble.
I'm sure there are a lot of people on here with more experience with it than I have, but that's my $.02.
I have a blog post about installing my seats that includes a couple photos:
http://www.1971chevysuburban.com/unc...-you-turn-left
I hope that helps!
james