Our spyder is probably a bit different than others, but moving the pedal position in our car would not be that difficult.
We are using a stock 911 pedal assembly. To move it rearward, we would have to clearance the firewall and fabricate a new firewall to accomodate the brake master. This would also require modifications to the brake lines that join the master cylinder to accomodate this move. Not that big of a deal since we had to hand build them to start with. The clutch is a cable and the throttle is a cable. Piece of cake for those two.
On our 911 assembly, it would be a little difficult to do service work on the brake cylinder, but not impossible.
Alot of people are using nifty little aftermarket brake/clutch cylinders (CB Performance?). What did the car you sit in have?
Another thing that makes a significant difference in pedal reach is the angle of the seat. Steve is quite a bit taller than I am. He keeps the seat all of the way back and drives without a lower cushion. We propped the front of the seat up about 1 inch with spacers. This let me slide down a little in the seat without sliding too far forward. Might try that too.
angela