You can upgrade to Z32 brakes. They are 4 piston calipers. You have to do some screwing around though. For more info, check out Al Abadilla's car at <
http://www.conecrazy.com>.
You could also check with SMC products. I know Steve either has worked out a BABK or was working on it. Kyle Davis was trying to get a group deal going to get them into production but there weren't enough takers.
Geo