I have used Magic Lantern on my 600D to get 4fps at 1/4sec exposures. Examples from these threads:
http://www.iceinspace.com.au/forum/s...ad.php?t=87782 (ISS and sky tour)
http://www.iceinspace.com.au/forum/s...ad.php?t=87283 (Moon and planets setting)
http://www.iceinspace.com.au/forum/s...ad.php?t=87599 (Stacked Omega Cen image from video through 12" Dobsonian)
Cheers,
Tom