A while back I posted a question about which camera and I wanted to provide some new information about it. The problem was the Hercules cameras don't seem to be available any more, and finding a webcam with at least 720p, good frame rate, a form factor that will fit in the available Inmoov eye mechanism (both old and new versions) and cheap enough was hard to find.
I think the latter is important because having stereoscopic vision will become more interesting as functions like what Alessandruino posted recently become available.
Some of my camera investigation is here, where I've linked to a $25 720p cam that should fit. It is on order, but I will update that info when I have had a chance to implement it.