Best answer as chosen by user mcgra: Camcorder for theatre work
You will probably be advised to buy Sony, Panasonic, Canon etc.etc. as we all have our favourites. I am a Panasonic fan so I will suggest the HC-X920 as it has a good spec for low light conditions - 1.6 lux. Normally the bigger diameter lens will give better low light performance.
You mention high speed for dancing but low light and high speed filming don't normally go together as the shutter speed does not allow for decent exposure. I have found that most camcorders perform well for sports action given good lighting. If you need high speed filming, a sports camcorder may be the answer - GoPro.
In my camera, a Panasonic HC-V700, a 32Gb SD card will give over an hour of video but some cameras, if left to run by themselves, may switch off after 20 minutes or so - check this before you buy.
Hope this helps.