While I would tend to agree with Oswald - I think it is a distinct possibility that DELL will offer it for the XPS 2, no guarantee of course.
They did go a little bit out of their way to announce that possibility with the XPS Gen 1. The Gen 1 was only out for a year and it had at least one video card upgrade.
I would imagine it would happen with the next refresh of the Gen 2 if it happens at all. You have to remember it takes time to release a new notebook and the procedures that are required for doing so - with DELL releasing their Lexus line soon. I don't forsee a new radical design for the Inspirons anytime soon.
In the scheme of things the Gen 2 is a small, niche market tailored to gamers in particular - and DELL with their pricing models are beating Alienware and others pretty good at the moment. They will do what is necessary to keep that.