A couple of things:
First, please chill with the photos. I thought you were just trying to show us some examples, not your entire portfolio of the event.
Second, the answer to your question is obvious. If its dark you can either do one or more of the above: use tripod, higher flash, more flashes, higher ISO, smaller DOF, lens with really good IS. The only "trick" that I can think of is to simply underexposed your shots by nearly a stop to gain shutter speed, then bump it up in post. I do that a lot and my 50D handles it just fine. I'm not sure what you expect if you want a wide DOF, no tripod, and low ISO - especially in REALLY low light.