My number 1 inspiration to study chess and design variants of it would have to be the actual game of chess! Chess is by far the greatest game ever invented. Greatest board game at least. It's simplicity at base of it's grueling underbelly. A black and white jungle. I love chess.
I really suggest that you check out, if you haven't already, the greatest movie ever made, Searching For Bobby Fischer. An amazing film that illustrates Josh Waitzkin's love for chess. That movie inspired me also, to study the greatest game ever.
The Chess Variant Pages are also another inspiration of mine. Seeing all those different variants made me jump at the chance to design another bigger and better variant.
Wau Chess was inspired by the Star Trek Tridimensional Chess Game. You can see a great picture of a Star Trek Tri-D chess set by clicking here.