If you're good with c++, you probably COULD do dungeons by ditching the cell map and using a g3d mesh for the entire map, but of course, you'd need decent programing skills, but I'll assume since you're looking for game engines, that you have such. However, something like OGRE, Irrlicht, CrystalSpaces, or Delta3D would be much better IMO, as well as easier and better documented. Have to do everything from scratch, but at least the 3D effects are nice. All generally have a handful of good samples.