Despite those thoughts I still haven't had a look at unicap yet, still too many other things TODO first.
Well, I just wasted another 2 hours trying to get my 5+ (!) year old webcam working which is still unsupported in Linux (intel pocket pc cam cs780, even though CS630 and CS430 are supported). Ironically, in Windoze everything "just worked."
Based on my tests I am suspecting that this is a lib/distro-independent issue, and as such am also wondering what will happen with pd/gem on Linux in 6 months when most of the other distros pump out their next release with libs similar to Edgy (maybe some of them already are?) leaving gem video for all intents and purposes broken. I also looked at the videojack project Mathieu pointed out and it really looks, well, promising, but it is by no means a complete and/or well supported product despite its huge potential. Perhaps this video issue should be bumped higher on the gem TODO list given the current situation?
Thanks for all your help!
Best wishes,
Ico