Hi, I have some black light expirence with 7d. First of all you must to change all settings to manual (as you know) and to disable all auto cerrection settings (peripheral illum correct, Auto lighting optimizer, higlite tone priority, long exp. noise reduction, iso noise reduction). I been shoting at ISO 800 and f 2.8. If you are hendheld it's gonna be not so easy to keep focuses so be ready for more takes. Images here are a bit darker due to compresion to JPG, in the orginal footage I have much more details in the dark. Lot of cinematographers suggesting to change picture style as well and to lower contrast (you'll get one stop more ) and sharpnes. There are some nice custom pic gamma profiles which you can download to your camera.
http://www.cinema5d.com/viewtopic.php?f=64&p=88923
http://www.cinema5d.com/viewtopic.php?f=64&t=7104
http://marvelsfilm.wordpress.com/2009/10/19/canon-7d-picture-style-with-cine-gamma-s-curve-free-download/
In this scene I used two 650W fresnel lights (with dimmers and difusers) , One as a key light and another as backlight. We also used some practicals and bulbs on the bar. In my opinion the key light was to hard (you see spots on his face), at the begining it was ok but then the singer start sweating and it changed a lot. Hope that it helps a bit.