I found this little gem a while back, but neglected to write it up here.
Keith Thompson is a Canadian artist working, apparently, out of Ontario. He starts with line drawings and works his way up with multiple layers of transparent color glazes to produce the final work.
His gallery is extensive, and well worth your time. I've lost an hour or two in browsing his work; if this keeps up, I'll be making some blank space on a wall to fill with one of his lovelies.
The Undying Flagellant:
And the Yokai: