Thinking About Buying a '96 - '98 3500 Crew Cab

I need a good heavy duty truck for building-construction work and recreational camping and towing, but I will/can not shell out $40k for a new Sierra 2500HD Duramax. I figure that for about $10k in cash I can get a good used diesel crew cab. I've looked at the Ford and Dodge offerings. I'm not a Ford guy and while I really like the Cummins in the Dodge, I don't like much else about them. So, I'm thinking GMC. I like the classic GMC look of the single headlight W/T front end from the mid-90's and it seems like these trucks have a lot of potential for people who like to upgrade their vehicles. I'm thinking I'd go with a 6.5 turbo diesel with a 5 speed (it looks like 90% of these models were automatic). Over time I'd probably build a new shortblock with better pistons (lower compression for higher boost) and swap out the IFS front end for a Dana 60 axle with leaf springs and 33" tires. Other than that it would have a cab height fiberglass bed cap, a lumber rack, custom bumpers, a winch and a locking differential in at least the rear dif. Anybody see any areas where I might be missing something or know of some problems with these vehicles.

Below is a picture of the kind of platform I'm thinking of starting out with, -- Matt

http://girdwood.net/fire/u15001.jpg