The only thing you can get that will bolt straight on are Billets or Pretechs to the best of my knowledge. H**** Blackbird ( or something) calipers which have three pistons on the outside working against a pad on the inside would probably fit but would need adapter plates.
Only floating piston calipers will work (with an adapter), but to the best of my knowledge I wonder, whether there will be any substantial gains over the old single-pots with a nice 14mm brake pump and some nice EBC sinter pads.