GH2 has a variable movie mode that lets you set the speed, but only to specific increments.
http://prolost.com/blog/2010/12/5/the-panasonic-gh2-dslrs-and-funky-frame-rates-for-creative-e.html
"One of the things that piqued my interest about the GH2 was its “Variable Movie Mode,” which purports to allow over- and under-cranking. Turns out this feature is not very exciting in practice. Panasonic’s site shows what looks like a broad array of speed options, from “80%” to “300%.” However, it soon becomes clear that the increments, 80, 100, 160, 200 and 300 percent, are significant in that they represent frame rates likely to be available on almost any camera.
If your base, 100%, is 24 fps, then 80% is 30 fps, 160% is 15 fps, 200% is 12 fps, and 300% is 8 fps. My 7D has 24 and 30, and if I wanted 15 fps, I’d just shoot at 30 and double in post. Same with 12 and 24. And if I wanted to shoot at 8 fps for some unprecedented reason, I’d shoot at 24 fps and speed up 3x in post."
In my opinion, the 300% rate is sorta useful as a psudo time lapse. I took some footage this way a couple of weeks ago and will be posting the results once I set my edit room back up (just moved!) Even with an 80mb hacked rate, I was able to get about an hour of footage on a 16gb card.
