Addonics or SIIG may make a card like this but they most likely will not be processor based. You may be better off just getting an adapter and using a good controller from Adaptec, 3ware or Intel/LSI. http://www.adexelec.com/pciexp.htm#PEXP4-SX-4/1
The adapters make the card exactly 3 motherboard standoffs higher so where you mount the card just screw in 3 standoffs first then attach the card.
250 MB a sec (each direction) shoud be OK for data transfer.