Rob is dead on. The only major drawback to switching regulators is the interference that can be induced in the delicate video signal. Fortunately this is an easy fix with a couple of capacitors. The cost of a switching regulator is negligible relative to everything else in the film/steadicam world. You can get a really nice adjustable 3-amp DC-DC switching regulator (Power Trends) from DigiKey for about $18 USD. Then a couple of bucks for capacitors, wire, a trim pot, a pico fuse (to protect against shorts), heat shrink to cover the board when you are done, epoxy and you're all set. These regulators are very efficient, produce a lot less heat (wasted battery power), don't take up that much space, don't weigh much, all said and done for under 30 bucks.
Hope this helps, if you need more info or picts let me know.