Just wanted you to know, that I've been following your thread for a while and I think this truck is going to be completely nuts. I can't wait to see what this is going to do!
However, as much as I love RCSB's (obviously, I've got one myself) I think that having as much power as yours is planning to have, with the short wheelbase of a RCSB, might be too much. Mine is a blast to drive, but if I had any more HP.... I don't know. Maybe ask Lance how he felt with his, his put down somewhere between 750 and 800hp, and I remember him saying how his almost put him into a tree a few times.
I know that this won't be your daily driver, it's going to be a dedicated race truck - but traction is my worst enemy right now. And I've got less than half the HP as yours is going to have. I think that keeping it a longbed will help A LOT at the track. Just wanted to throw it out there. Either way, I'm really excited to see this thing get built!
Also, I agree with Six_Slow - that's insane that you scored a shortbed for free. I severely lucked out with mine, when I bought it for $1400.