Thanks for replies, guys. Some thoughts:
MEDIK418: I couldn't find any web site for IPS, but I found a few references to them. It appears that they are out of business, and I read some negative feedback about their suspension systems. Anyone know if they are still in business, and if so, any web site?
Kamaro Killer: With all due respect, I think you've completely missed my point

There's nothing creative about buying a car like a Cobra, no matter how good it is. It's about building a unique car, and it's about doing it myself. Buying a new car off the lot completely defeats both those purposes, no?
LX5091: Thanks for positive note, I think you're understanding my quest.
Dark_5.0: That sounds interesting, are the live axle mounts the same for the Fox body cars as yours?
Anyway, I really appreciate all the input, I'll keep you posted if this project ends up having an IRS or not.
T.