A Question on Speed

I've seen and read lots of great tutorials on making beautiful slow motion, and awesome timelapse sequences with DSLR cameras. My question is, how do you remap the time of a clip, essentially combining the two? To clarify, I once took a clip shot on a Canon HV30, a consumer grade camera, recording in 24p to HDV tape. After all the transcoding, I dropped the clip in the timeline, and using the time remap tool in Final Cut Pro, slowed the clip down, and gradually brought it up to normal speed.
Is this possible with DSLRs, and how?

Granted, I've haven't done a lot of test with the camera, so I still have a lot to learn and figure out, but I've tried using the time remap tool, and despite looking cool, it doesn't look as smooth or natural.

For anyone with more experience, please feel free to drop some knowledge on me. To give another example of what I'd like to achieve: I have a clip of someone kicking a soccer ball. I like to have the player running up to the ball at faster than normal speed, gradually step down to slow motion as his foot contacts the ball, and then snap to normal speed as the ball goes flying off.