Anyone have any good suggestions for big-brake kits for 13" wheels?

It very much depends on the rim. Big chunky cast minilites versus spun alloy mags or steels.

278mm disks with Hi Specs is the largest I have seen.

Rich Miles' R1 Striker brakes

very snug.

- Jim

Aye... they're pretty HUGE!

one of the biggest factors is your upright design. on the escort calipers he has, the brake run a long way inboard, where the only constraint is the inner rim diameter.

On more modern cars the disk goes on the outside of the hub bringing the caliper outboard with it and then you run into clearance issues with the inside of the spokes and the radius where they turn onto the rim.