Quick estimate for Cell:
7 SPE SIMDs + PPE AltiVec, each doing 4*32-bit ops/cycle.
PS3 cell is clocked @ 3.2GHz.
bitcoinhash is ~6350 cycles without native rotate.
8 * 4 * 3.2G / 6350 -> about 16M hash/s.
About on par with a hexcore K10.
I get slightly over 17Mhash/s per socket from AMD Opteron 6128s, 8x2GHz. So that sounds pretty fair. TDP? ~50W?