Mike,
I'm contemplating the auto-to-manual swap on my car too. A few thoughts:
1) Do you already have the T-10? If not, why not go to a 5-speed and get the bennies of overdrive? Negatives would be that the end cost is probably more than what you could pick up a 4-speed for and it won't be a true "bolt-in" like an original equipment trans would.
2) An assembly manual should show you exactly how the pedals are mounted. If I remember correctly, I think both the auto and manual Vette pedal assemblies use a common p/n bracket that bolts in and out making this part hopefully easy.
3) The easiest(?) way to get the parts is to find someone who is parting out a manual trans car that is willing to sell you the complete assembly. You could also look for them at swap meets but be sure you know how to identify what you're looking for. Buying everything new may be possible, but probably a bit expensive.
4) I believe you will also have to add a stud on the frame to hold one end of the clutch linkage bar. Automatic car frames probably don't have these.
5) I think that the trans crossmember on automatic frames is a bolt-in piece whereas the c/m on a manual trans car is welded in. If this is the case,it should help make the swap easier.
These are some of the things I've found so far. Please keep in mind that I haven't actually done it myself yet!
Good Luck,
Jeff