This is a really good garden tool storage idea. build the back wall of the shed in a bit from the structure, and then frame in some doors for the exterior wall, using the solid back wall to store tools pegboard style. You could also keep pots, fertilizer, etc in there. I may just have to add this on to the kids' playhouse plan.
Utility Armoire = GENIUS! - These clever homeowners repurposed a $20 yard sale purchase to hide their utility meters/hookups AND gained some attractive storage space in the bargain. (tutorial Shabby Glam blog)