Port TilemapKit to a SceneKit/Cocos2d-x 3D renderer to render tilemaps in 3D. Tiles are extruded to 3D shapes with configurable "extrusion depth" and textures (defaults to using tile texture for all faces).
The cuboids use the tile graphics as texture for all sides, with optionally being able to use different textures for top and bottom (or any) faces.
The first versions will focus on orthogonal maps as they benefit the most from 3D extrusion.
This would allow for 3D world space for games that essentially still have 2D gameplay, ie platformers (Duke Nukem Manhatten Story comes to mind).
I estimate this task would take about 2 weeks.
PS: this would also pave way for a voxel renderer for game characters which could also be extruded from 2D images and an (optional) heightmap image. Just another idea I've been contemplating like so many others. ;)