The other thing to keep in mind, if you're not doing it already, is to shift-space (single frame) instead of just doing the usual 10-frame turns. Sticking to longer frames only gives the replay a bit of an unusual rythm to it, as the character moves, stops, moves, stops, etc.
Whenever I'm messing around with single-player replays, I go through almost the whole thing a frame at a time, tweaking things as I see them. This can really give you a lot more fluidity.