there are very few that have built engines and DD them. guys that build them generally use them for fun or drag trucks. Most that DD them will not be running around on 800+ tunes either. For one, you will need 4wd all the time to even use and Two, you get that high in the HP and you will wear the drivetrain out quickly.
the other thing is turnover rate. ive seen alot of guys (not on this forum) that have built their engines and made awesome power, then sold the truck not but a year or two later because they had too many things nickle and dime them (engine related or not) or it just wasnt as well rounded of a truck as they had thought.
I agree. 1000hp dd is not gonna last. These magazines make people think it could be done.