Has anyone tried this? Firstly, I'm interested in a good P&S that would work well with off-camera flash (with ability to turn off preflash) as well as using off-camera flash with any point and shoot camera (I work in a student organization, so being able to couple my OCFs with my peers' cameras would be good). Is there a tiny OCF but relatively powerful enough for bouncing that would fit nicely in a purse with the point and shoot? I ask because I often have to attend parties as a participant, not just a photographer, and being able to take photos with OCF while being able to dance, etc. and not have to watch out for your equipment would be good.
There are also "smart" optical slaves which can be set to ignore pre-flashes which will allow any manual flash to be used with a P&S. But the down side of optical is every camera in the room will trigger your slave flash.
Your desire to work universially with the cameras of your students is a tough one, and the "smart" optical slaves mentioned above sounds like it may fill the bill, so I would look in to those.
If you just want a camera and flash combination, with out the common use by others, the Canon G series cameras like the G12 and G15 have a hot shoe on them that works with the full line of Canon flash units, including some fairly small ones like the 270EXII. The 270EX is pretty small and portable compared to full sized flashes, and it does allow bounce flash when mounted directly on the camera. You could also combine a short or long sync cord with the 270EX to get it off camera and maintain full ETTL or Manual flash contol, but that would be only one flash, not a second off camera flash. Plus of course the cord gets awkward, but it does prevent interference from other flashes.
Basically any P&S w/ a hotshoe works best. E.g., Panasonic LX7, Canon G15, etc.
Optical slaves are crappy in general...P&S generally don't work well w/ them because you don't have enough control...
