I have yet to see a 2500 Suburban in the GMT900 body since they came out three years ago. In fact, you ALLEN NELSON posted a dyno session with one you did mods and tune on. Look here for that VIN or in your files at the shop

Or you could do like others here and hope you get one from eBay. What I can do is run VIN's to see what option content they have.

Looks like the VIN Greg found and Jeff posted is a 2500 with a 4-speed Hydramatic...