I love the game Spelunky! It's a 2D platformer famous for its difficulty. The art, the music, the controls, the gameplay is just splendid and I wondered often in what direction the game could take, would it transcend into 3D space. The only thing that popped into my mind was Mario Galaxy. I think the style would do Spelunky well, but not sure if the gameplay would transcend well into 3D. Mario id the jump from 2D to 3D well though, so why not Spelunky!
The spherical map style would maybe not work for a normal Spelunky level, but it could be a sort of hub world, like in Mario Galaxy, that connects to other levels that has a more normal camera & conventional leveldesign used in Mario 64 etc. Great fun image to work on!