Windows XP Professional, exclusively.
I was thinking along these lines: Windows sees two displays as a one big 2048x768 display. So, basically I create one big Pygame Surface (no pygame.FULLSCREEN), and position it in the upper left corner of the screen. I divide that Surface in half, and do the GUI interface blitting in the (let's say) left part, and I render my videos in the right part. Will that work?