Note: I make no guarantees about the applicability of this template to your own case. It worked for me and I hope you find it useful, as well. The biggest potential issue would be with the cutaways for the power and volume buttons, which are pretty large on my case, but it should be easy to remove them if your case doesn't have them.
Here's how it looks when it's all finished:
EDIT: Here's a slightly better picture:
I made this BMO design along with a couple of other Adventure Time designs, ready to print:
Best show on television.