Awesome build! I'm very tempted to try to do this myself. Can't use a crate engine and pass smog in California though. You have to use an engine pulled from a newer car. Looks like the stock Corvette cats would fit since they are so close to the exhaust manifolds.
I wonder if it would be possible to use the LS4 water pump and accessory layout? It was mentioned in the Cayman + LS3 thread on LS1tech. Might be able to avoid having to use an electric water and power steering pumps. Looks like the alternator position would be a problem.
Bummer about the engine. At least you caught it before you fired it up.