Yeah, that's a nice board
. It's a shame the last slot is unusable if you have a case.You just need a better case. Look for a PC-K57 or Lanboy. Vendors are slowly coming out with cases with 8 expansion slots in the back and will fit 4 double spaced cards.
Or if you're very cheap, you can fit 4x dual-slot cards in the Antec 100.