Yes, I am aware of the limited RAM. But well, I think it can not be that expensive to track a dozen points in a 3D space.
I remember I saw something like this in 2D for GLCDs. So I wonder if someone wrote something similar already for 3D - just to avoid inventing the wheel twice.
Well it shouldn't be too hard to develop some classes for some basic objects and have methods attached to move them around. Do you have a display in mind? Perhaps an LED cube?