FWIW, the NMT forums seem to indicate you can use the lite BD menu to switch between standard and 3D. I'm still waiting for mine to arrive, but will be very interested in this as well.
Edit: Since the conversations I've read on NMT regarding BD menus and 2D/3D ISOs often included Halfelite, I'm sure he can speak more to this.
Edited by Digerati. - 12/28/12 at 3:10pm