I am huge fan of Scott Robertson. You should check out "The Skilled (or is it skillful) Huntsman)". He takes that story and several of his students run with interpretations of the story from character design and so on. Another good digital painter that I think you would seriously enjoy is an artist who goes by the name of Paper Blue--he is a professional designer--has a book out called "the Art of Paper Blue". This is right up your alley.
I was a beta tester for Mischief for a couple of it's elements--it has what is called an "infinite canvas" --Nick Harris demos it on youtube--but it sort of died out after source forge acquired it but that infinite canvas and the ability to "pin" images to different points within that infinity was really cool. It is still around but have never seen an update so back to the Rage we come a runnin'.
Krita is really good but it is a bear with a bee up its nose to navigate sometimes--so artrage rocks and people like you seem to make sure that we never forget that. LOL!