Cinepaint, I believe is for frame by frame work.
I've never used it... I just know it's there.
http://cinepaint.movieeditor.com/
These folks are talking a good game:
http://www.zs4.net/
but they are in very early alpha.
I have seen editors that have filters for different things
(kino I think), but I think most linux editors are for DV.
I'm going to try that "zs4", and I'll post back in a few days.