A larger version of this is the background for my best friend's birthday present that was organised by a mutual friend of ours.
It is the first image that I have used my new Intuos5 tablet for and I am very impressed with it. It is also the first time I have done an entire image in PaintTool SAI, with the exception of the glowing on the spots, that was done in Photoshop CS2.
Execution belongs to Hanyoutai.