I would ignore those guys at the S10 forum, they've made it more than obvious that they haven't a clue what they're talking about.
As I'm sure has been mentioned on this forum, the 6.2 was designed from the ground up by Detroit Diesel as a Diesel. The 6.2 (6.5) if pushed, will make about 300 horses and still be reliable. In the end they are very reliable engines, can make decent power, and are realitivly cheap and easy to maintain.
I'd say go for it and run. If you can find the room and money, maybe even through a 6.5 turbo on it. Good luck with it. I think this'll be one awesome truck.