The cheapest way is to buy a Promise Ultra66 controller and solder a resistor to make it a FastTrac 66. Although it does void your warrenty, it is a RAID card for more or less $25.
I think I heard that the last flashing utility wouldn't work on modded Promise cards, although the latest BIOS flashed with an older flashing utility would.
TheTechZone.com has a link somewhere telling you how to do this...as does HARDOCP, I just don't have them bookmarked.