We currently don’t have a memory core available for public use. However, I wouldn’t be intimidated by the datasheets. It really isn’t too complicated to get a simple controller that just handles page writes / page reads. In fact, it is -easier- to handle only burst transfers.
Our memory cores and the board handle speeds up to 133 MHz without problems.
I’ll give you a hint – use a FIFO (1024-word or so) to buffer data coming from either the USB side or the camera interface. When the buffer gets to be half full, signal your DRAM controller to make a full-page (512-words in many SDRAMs) transfer. Likewise, you can use the half-empty signal to move data in the other direction.
If you keep transfer lengths restricted to multiples of the DRAM page, you can make a controller than only deals with page bursts. Life becomes a lot easier!!