I was actually thinking of doing some similar experiments soon.  I guess one option would be to decrease the triangle count on the models as the camera gets further away.  Another option could be to make 2d versions of the 3d meshs and as the camera gets further away switch to the 2d version in place of the 3d mesh.  The camera would probably have to be pretty far away for that to work though, and I could see other visual issues arising from that.  Maybe those solutions are pretty obvious though haha.