it sounds like you want to grab a sexy X48 platform board ^^, I don't have any experience with this board, but I'm about to go out and buy one today.
it support crossfire, you can get in DDR2, or DDR3. If your going to be an Xtreme overclocker, if you do choose the X48, go with Foxconn's new-ish board. The options in the BIOS are astounding from the reviews.