If you think there will be a speed benefit from having a single surface mesh system, then you are quite wrong. The single surface approach only works up to a certain number of polygons. Once you go over that number, even moving one vertex will have a negative effect.
It will be slower.
It will be slower.
I've not found that to be the case. And I've tested up to the maximum number of vertices possible on a surface. Granted it was only about double speed on a lot of vdeocards, but double speed is still worth doing, i think.