Wow, thanks for the replies, everyone. I feel all warm and fuzzy.
Scintilla - the way I did it took several steps. First, I worked out the lipsynching for the glasses-reflection clip. I exported that as its own AVI, then used ... ImageReady, I think, but it was quite some time ago so I don''t remember clearly ... to separate out the individual frames, and for each frame, replace everything bounded by the glasses frames with a single colour that wasn't used elsewhere in the frame, in this instance RGB 0x00FF00. I then sequenced the stills back into an avi and placed that avi in the timeline on Video 3 with Transparency set to Alpha Channel (I think - I'm at school right now and not in front of my editing computer) set to RGB 0x00FF00 (which makes everything that colour transparent).
After that, I took the clip of PenPen, threw a noise filter on it, and placed it on the timeline in Video 2 and Video 1A. I then resized each instance of the clip and moved each one around so that it was positioned at an appropriate spot in one of the lenses. Voila!
If I had it to do over again, I'd export just one frame to a bmp, then colour the lenses green and set the transparency so that the bottom half of the picture (or really, any part of the clip with motion in it) was transparent, then overlay that bmp over the entire sequence. Would have been way easier.