That's exactly how I'm thinking as well mate, i'm going for the Dolphin battery too get me up and running, and from there i will probably hit hobbyking for some lipos, or even 18650/26650 cells. I've just spoke to a mate of mine who used to make custom carbon fibre body kits, for mini's back in the day, so we're going to figure something out like the stealth bomber, a triangle box around the frame to mount the diy battery option, so it's built in permanently, and if I go on longer journeys, the pre built battery will still fit in there, along with mounting the lcd display.