Online resources for designing a high frequency, high voltage power supply that is happy driving a capacitative load are not particularly easy to find. 

The closest project to ours which we could find was this one:  http://www.kobakant.at/DIY/?p=4101, http://www.kobakant.at/DIY/?p=2992  (and for those that haven't seen it, the rest of the Kobakant site is also worth exploring!)

Jeri Elsworth also made a few videos about EL materials (above is her exploration of a self-oscillating EL supply). 

And here is a video that tears down another (self-oscillating) commodity EL supply: