Ken had it right at the beginning of April. ASCOM cameras only, If you want SGP to run with your camera get an ASCOM interface for it. He was joking but I think that would have been the way to go. Even if he then wrote and maintained the ASCOM driver it would separate SGP from the vagaries of the continually varying camera drivers.
As for an ASCOM interface for a generic DSLR, there's nothing to stop this being done. I suppose that you would have something that will operate the shutter, I've seen a serial port line used for that, then find the image file, open it and read the image data. I hadn't considered that the image file and/or location were standard.
The trick will be avoiding the bloat that will inevitably be demanded.