obviously I couldn't sleep without having this done...
@Jaime: I tried setting 75fps @ 320x240 which also works fine with Gem.
v4l cpu consumption is much lower (35% to 40%) in debian unstable (I was using sidux live cd for that) would be interesting how much cpu consumption other operating systems have compared to this, especially mac os-x. I'll start a new topic on this.
Martin