I guess I would need something small that I can easily hide.
I'll be in the 15th-ish row on the far right side on the floor.
Hmm... I've videotaped a lot of shows... this does not sound like it's going to be an easy one to pull off.
As far as "hiding" the cam, you need to be able to hide it while getting in the door to the venue (very easy), and you need to be able to hide it from view while you're using it (not so easy).
It goes without saying that you can't hold the cam up to your face when filming. And from the 15th row, unless there is a steep slope to the stage from where you'll be sitting (which I kind of doubt), you're going to have a really tough time, unless security is just non-existent at this place.
If you have a few a friends with you at the show, use them to help you hide the cam from view.
You might want to check this thread I started a while back about tripods and monopods. That Hakuba monopod might be just the ticket for you:
http://taperssection.com/index.php/topic,78399.0.html