Not one, but TWO programs that are dealing with 3D have been published !
BBgunner, by Lucas O. Wagner (who also created bbmatrix and an avid developer on bitbox) , is an opensource, two player, split screen, 3Dcombat game where you chase each other - and try to kill your opponent : the first 3D game on bitbox and also the first two player game ! Now get your engines started and kill this enemy - amicably of course.
Bitcaster, also available on github, is a demo of raycasting algorithm, tailored for the bitbox. For now it's just a demo, not a game, you just wander in a maze of colored walls. Note that this 3D is filled faces / no textures. The next step would be to make a game out of it. The obvious idea being wolfentbit 3D but maybe you have another gameplay idea ?