Inspired by those great concept arts, I have thought about painting my case to look in the style of a NES or 2600.
Using stencils to get clean edges and then apply paint.
I probably will do this at some point, though not holding my breath on it coming out too good looking, but what the hell eh - It's only the case
Not sure how good stickers would look, I guess the best type would be like those Gelaskins you can get for your iPhones, but if wanted to wrap the Pandora properly you'd have to get on those rounded edges too, and that would be tricky.
Even with my old iPhone 3GS I had, I got one of those Gelaskins in a Gameboy skin, the 3GS has a little curvature and when it came to that it got a little crinkled, I think it would be worse on the Pandora.
Like the idea though of decals, but for me I think a paint job would be best