Last night I was down at the Vivid fest in Syd. with the 7D and a 2.8 lens (24-70 I think.)
Really impressed with the low light capability of this cam.

Here is a video of a couple of girls dancing with fire...

YouTube - Sydney's Vivid Festival (http://www.youtube.com/watch?v=lwNm7Mfylrs)

And here are some stills (first time playing with long exposures)

http://pics.brizzly.com/2KWY.jpg

http://pics.brizzly.com/2KX0.jpg

http://pics.brizzly.com/2KWW.jpg

http://pics.brizzly.com/2KWU.jpg

These didn't turn out so well but I'm down there again to give it another go...

http://pics.brizzly.com/2KWT.jpg

http://pics.brizzly.com/2KWP.jpg

http://pics.brizzly.com/2KWN.jpg

http://pics.brizzly.com/2KWJ.jpg