Anyone know of any good portable electrical supplies for playinglive?

["steve.sandberg" <steve.sandberg@earthlink.net>]

Hello all,
I've been possessed with a desire to take my looping to the streets of NYC!
Does anyone know of a good portable (hopefully inexpensive) electrical
supply that I could use?  I'd like something that could let me play for 3 
or
4 hours, and I'd be plugging in an amplifier, 2 synth modules, a kaos pad, 
a
samson wireless mic and an edp -
thanks!