IFAIK, the answer is "no" and I do the same thing with the still snap. I bought a black, gray, white target and shoot stills until the exposure (by histogram) is right. I also set a manual WB with the still and take a final still of the target with the exposure and WB for later reference. If I have the time, I delete the other stills, keeping only the one reference still for each set.
The more I learn about shooting video with the 7D, the less I feel like a videographer and the more I feel like a photographer.
From What I gather the gamma level is different in Recorded Video vs in a still, so I just record like two seconds of video and then view the histogram with info button during playback.
Also, I find that enabling Highlight Alert is my friend
Yeah, I scoured the forum looking for answers and the general concensus is no. I like the idea of capturing a two second clip before doing an actual take and checking the histogram then. I've been using my light meter, so at least the histo will be a nice back-up check.