One suggestion I have for when you do it: lots of empty space per flaming wick space. Too much kevlar and it'll just look like a flaming pile of nothing. The fire will engulf any form or definition.
I can't remember the website right now (Man, are we a helpful bunch of corkers, or what?) but I've read about folks weaving designs onto a large wire grid with kevlar rope and lighting that. They called it fire painting, I think. The image of a sun keeps coming back... I think they're based in Oz or NZ (Yeha, thanks, Rick. That narrows it down.) Very large, circusy shows...
UUuuh...
-Rick "Useless yet tantalizing information" Gladwin