i cant help on the drill pack cases...in my mind is a tray screwed into the car which will take a smaller tray inside it which carries a lipo and deans...or 2x bullets 4mm...so its kwik change. as you drop the tray in the connectors line up and engage...the trays could be some perspex or machined nylon.
something light anyway...hmm carbon fibre...

maybe held in by 2 velcro straps or some clips...
chris