Actually I do not recommend a laptop for 3D in general. The price difference to a desktop with comparable specs is significant and it´s not really fun to work on a small screen. For me, it only makes sense, if mobility is obligatory.
Two cards could be helpful regarding PhysX, but the question is, if you want to spend the money for getting some fps more.
Thunderbolt is cool, but there is not really much hardware out there supporting this connectivity and it´s way more expensive.