There was some discussion about using a series with wireless here:
http://www.alembic.com/info/fc_leapoffaith.html and, you may have to give consideration to the stereo/mono question as discussed here:
http://www.alembic.com/club/messages/394/25127.html?1140248111 I couldn't find the discussion I thought I was looking for. It still seems it should be possible to create a belt-pack with a hi-tech rechargeable battery and wiring to provide the same power you would get through the DS5. Sort of the same type of thing professional photographers use for strobes in high-demand situations, though that's typically more like 6v. I did a quick search and found this:
http://21st-century-goods.com/page/21st/PROD/MP3400 It seems like this, or something like it, could be wired to provide power to a portable DS-5-like device and hang off a belt pack. If it can power a DVD player for six hours, it should easily power a bass with LEDs through a gig.
Of course, if anyone is thinking of doing something like this, running it by Mica is always the best place to start.
Personally, I'd just plan on swapping batteries for every gig. I might have a different perspective if I were gigging more often than monthly these days. I'm not sure if anyone makes a 9v rechargeable that's worth using these days.
-bob