Almost all X58 (Socket 1366) boards are capable of SLI by now. Just check the board manufacturer's site to make sure. I've seen many folks satisfied with ASUS, Gigabyte, DFI, and EVGA's offerings although I wouldn't rule out other vendors' boards just yet.
On LGA775 front, only nForce boards support SLI. If that's what you're looking for, I'd suggest a 750i variant instead of 780i/790i.