What exactly are your reasons for using a flat profile in low light? why do you think it's better? In the end, the 7d isn't going to be able to capture a ton of detail in shadows at night, the camera just cant without adding noise and other junk.  I think it's funny how everyone is trying to make the 7d perform like a $50,000 camera, when it can't.  It's pointless to try and fight the limitations in my opinion.  You'll have better results if you shoot with the camera and cater to its natural tendencies, you will get a much nicer image.
I was part of a crew who shot some in store video for a major electronics chain.  We were using 7d's as b cams on the shoot.  We were shooting with the Neutral profile.  The end results were great.  The 7d out performed the A cam and actually looked better.  The footage was graded at a proper post production house on a proper color correction system.  There is more detail in the 7d image than meets the eye, it just takes a skilled colorist to bring it out.  I really think that shooting with any flat profile is not the way to go, but, that's from my personal experience and what I have learned from shooting with DSLRs in a professional setting.
Why fight the cameras natural tendencies? It's not a RED, it's a 7d/t2i/5d etc.