I did something similar, no art for it yet. but my case is a World of warcraft starter deck's case that I modified. it fits the DMG nice and tight, with little room for wiggle. I had to modify it but it was real easy to do. All it took was to remove the card deck holders (they ARE removable!) and cut the top side off one, the bottom side off the other, shave down the pegs that hold them in and boom.
I'd love to use your art in my design but it needs resizing...
