Doesn't anyone else in the band have a laptop??
Setup up multiple pc's capturing video and, just like you do with audio, piece together the videos with a video editor later.
or play the songs several times and comp bits of several performances over one audio track-- no one will notice if you do it right
(I once simulated a multi-camera setup this way for a 2-hour play by taping a week's performances, moving the camera each night and using the best bits)
** webcams suck... you need real cameras.
** what video editor do you use? I highly suggest you spend $50 for Sony Vegas Studio if you're on a PC.