I picked up some UNI UN-4229's from the local shop. I don't think they will work without some trimming. Cyl's 1&2 and 3&4 are so close together that there is not much room for individual filters... I have no idea how that guy got the individual BMC pods to work
The BMC dual filters look like a good option (but I'm too poor right now). Spacey86, I don't think you'll be able to run side covers on a pod filter setup as they stick out from the carbs without tapering in severly.
My next step is to get a sheet of the UNI foam and lay that down in the airbox, and swiss cheese the airbox top with a hole saw...