You really need multiple cameras to cover a concert. Especially if you have to stop/start record or change cards/tapes at regular intervals.
At worst, give yourself one locked off camera that covers the stage/venue from a nice spot and won't get obstructed and can roll with minimal operation. Something you can check on between sets.
Hard to say what you should do with the glidecam without seeing the venue, but if you can be slightly off-stage right or left you can get nice profiles of the performers. If there is a security alley b/n stage and the crowd try to get in there where you can get the crowd or the performers in that "oh-so-rock-and-roll" low angle shot.
Ideally you've got 1 camera grabbing a wide, 1 camera on your glide moving around, and a 3rd with a long lens and an operator who can focus so you can get CUs on faces, or details of the instruments being played, stuff like that.
With one camera and a 12 minute roll limit, your goal probably becomes working with the performers to grab certain specific tracks, since you don't want to roll out or overheat in the middle of that bitchin' 7 minute bass solo, or whatever.
Also, drift is going to be ... a problem ... when you try to synch long recordings from DSLR to a recording of the concert on whatever you are going to record the audio to. Long story less long - the longer your recording is, the more variance in the time base between the camera files and the sound files. Recording a concert without jammed time code is an excercise in manually snipping and nudging timelines that will drive even the most OCD person completely mad. I'm no expert on these things, but in my limited experience 2 XH-A1 cameras + 1 stereo mix from an 8 track portable recorder == absolute synch nightmare. I can't imagine that a DSLR and a "zoom" or whatever you planned to record the sound with would be any easier.
), but you'll miss all the stuff in between.
