For the clutch set-up, get an aftermarket master cylinder (wilwood or some such), and then have a line made from that to the oem slave. You'll need to tap new threads in the slave and put a fitting in it to mate up your new line.
The mount for the T56; Can use the JTR one. I made up my own because I didn't agree with the JTR design (bolting to the flimsy floorboards), but I have never heard of anyone having issues with that. With mine, I have more space for the exhaust routing.
BTW, I picked up my '94 LT1/T-56 (Z28) for $1400 Smiling all the way. I was going to go GN-Turbo, but couldn't pass this deal up!! I'm still not sure if I regret not going GN
For roll cage, I got mine from S&W for under $200 delivered:
http://www.swracecars.com/rolbarlist.html#anchor1158811
Tim