If I would have known that was you that I saw there last night, I would have gladly loaned you my 20d (not my 40d though

) and any of the lenses that I have. I had them in the car.
As far as all of your questions, sorry I didn't see them earlier.
There are people photographing there all the time, including myself, and it is totally not out of place.
The lighting in there when they have people on stage is not all that bad, but it would be tough to accomplish at ISO 200.
I do have a few film shots that were taken at an equivalent of ISO 400, but I don't think they would work very well for a band that is moving at all
this is a ISO 1600 shot, 1/250 at f/2.8 with no pushing at all. Only thing that I did in post really was some noise reduction and sharpening.
This was taken with 100 speed film, that I pushed 2 stops in developing. and then had to actually pull it back about 1/2 a stop when I scanned it.
I think it is one of the more interesting places in town to take photos, and the backgrounds are always changing, and when they have the satge lighting turned on, it is really not that dark in there either.