you may also try encoding with keyframe interval set to 1 (or 2) and the bitrate very high at 4000 (this is the max for divx afaik) and the 'big resolution'. this makes less motion frames (which normally need more encoding time) and then reencode it (when there's time) with the bitrate you want and the keyframe interval set to standard again.

but: you need a lot of disk space...