^ An add on would be almost as bad as carrying a seperate camera or device, which defeats the point.
Perhaps the easiest solution for an externally facing camera would be to put it on the back where the ports are. The camera would just need a small hole in the back like the rest of the ports there. It also could then be attached straight to, or as close as possible, to the PCB. Alternatively , the camera could be added to the bottom of the Pyra. The camera would then be mounted to the back of the PCB. With the screen folded horizontal in line with the keyboard, and the trigger button used to take a photo. Would probably work well ergonomically .
If it's to much to add it to both Pyra versions , then adding it to the 3G version would make sense for reasons previously given. The GPS in this model would be great for geotagging photos also.