Hi guys! Thanks again for all the help and encouragement! The Camaro should go into my shop this weekend for disassembly, so I can see what I'm working with.
As far as the engine goes, I've researched, and looked, and shopped, and I think I've come up with potentially the answer. The LQ4, or iron block 6.0L that has been suggested. I have seen complete motors for $1500 +/- $200, all accessories and wiring, etc. included. This is a truck motor, they make around 300/370 stock. Mild cams can get them up to 480/450 with the stock iron heads! If I have the budget, the L92/L76 combo ($1000) can put these things out to 550/470 range! That's being completely streetable, with good mileage. They'll rev out to 6800 RPM, too! Should make generous use of that T56!
So I think I've settled on going that route, as it seems to be the best budget/power option for this project. They aren't much heavier than the aluminum LS motors, either, esp. with an aluminum head swap.
So now it's just finding a deal on a complete LQ4 sometime in the next year, or so. The sooner the better, as far as fabrication goes, but I have some time before I need it.
Again, thanks to everyone! The upcoming long weekend should give me a chance to get the website up and posted, so I can chronicle the entire process starting with getting a non running car up the grade into my shop.

FTW!
This has to be my favorite forum I've ever been to!