I picked up a Neewer 12V 4500 mAh battery off amazon.ca for a decent price that came with a charger and extension. To contrast, the 8 AA batteries I was using before were rated at 1350 mAh each; no idea how mAh works, but I'm pretty sure the numbers don't stack all that much. The broken English manual that came with the new battery was priceless (Something about a GUN? ...Or to not open if career or battery may bomb)
I cut one end off of the extension and connected that to the soundboard. While I had the pack open, I wound up some of the excess wiring around the speaker mounts and zip tied them for good measure. The other two ribbon cables for the light kits are velcroed to the shell for easy assembly/disassembly; it just keeps them from hanging all willy-nilly.
...of course without thinking, I stuck the battery to the motherboard right where the pack would rest on the display stand, but it's an easy thing to change!