Hip Hop Slave Sabre

Look at Lithium Ion rechargeable batteries, they are not small but they are very light which will be your main concern.

The inverter set up as it is at the moment is only 109g with batteries so pretty light really.

The invertor can be made so it doesn't whine. do you have a link to the EL sheet you used and the specs for powering it?

I have no clue !!! I have a few bits of EL sheet from all over the place, most of it is fairly old - the one I do know the provenance of is the stuff I got from http://www.mutr.co.uk/ which to be honest is not very bright and the electrical connections are weird - so look around but don't get it from there (but I mutr.co.uk do cheap inverters for you to pull apart and make small bike sized ones) - also don't get it from http://www.rapidonline.com as they use the same stuff as mutr.co.uk (but if you want to experiment are very very cheap).

I know surelight sell the good stuff but they are very expensive.

Sorry that's the best I can remember, search around it is not too hard to find.

For power - 9V (4x AA or AAA batteries) of inverted power.