I've done it. You might want to use after effects or something similar. Take the uvSnapshot. Put it in your compositing program. Move your movie layer under it so the texture is were it should be. -Render your movie.
In maya you create a movie fileTexture and asign your film to it. Tick use image sequence and it should work. This will also automaticaly create an expression which goes something like "yourMovieFile.frameExtension = time" this means if you are at frame 25 in your timeline your movie texture will be at 25 as well.
This is somehow inconvenient for the animation of eyes mouth etc. So delete the expression. Done that you can go along and keyframe your movies frame extension like any other atribute.

good luck