(ET) Go Cart power alternative

["Solid Technologies" <solidtech qwest net>]

All,
  I work with Royal Rangers at a local church here in Colorado Springs (I
mostly work with the 7-year-old Ranger Kids).  I was talking with the
Outpost Senior Commander this evening and found out about a new older-boy
program for Saturday evenings that involves go carts - building them from a
pile of parts.  Well, I mentioned that we should have (at least) one that
uses electic power vs. an ICE (quieter, less maintenance, etc.).  So, the
request for the group is specifying and tracking down an appropriate
configuration.  My initial thoughts are:
  Motor: From an E-15/E-20 (where can I get one?)
  Contoller: I think I've seen someone selling one (who/where?)
  Speed pedal: Spring loaded gas pedal linked to a variable resistor?
  Batteries: Maybe a set from the local Sam's Club (or maybe a set of 3 ___
that I've seen a couple of notes on).  Or maybe a set of 4 @ 12V for more
speed?
  Charger: I have a spare 36V, but if we go 48V then what?

Input please.

Thanks,
--joe

Joseph Rock
E-15 in Colorado