So I finally got my head sort of wrapped around how time remapping works in Final Cut Pro 7.
However, I'm running into a strange quirk. Unrendered, the remapping plays perfectly. After rendering, however, there is a one frame jump back after the speed keyframe. So; going from fast motion to normal speed has an awkward jump at the transition point where it returns to a slightly earlier point in the video, then continues.
Anyone have any light to shed on this matter? (And no, we don't have AE yet, unfortunately, so this is pretty much our only option. Motion....)