If it were that easy, it probably would have already been done. The strobist group on flickr is currently 56,000 strong and growing. There's quite a few electronics nuts in there, as my eyes have glazed over more than once when reading an in-depth thread. I really am interested to see what you can come up with. If you start making progress, I'll certainly buy another Canon unit and help you test the thing. I'd even try my hand at creating some front-end software in case you wanted to make it programmable (however, my Visual Basic skills are relatively limited..but I always seem to learn whatever I need to in order to get the job done...just takes me a good while, though).