The “in WordPress” part limits your options (and also my ability to give any useful insight). So… no answer. Sorry.
The Thing What Joe Is Talkin’bout:
I haven’t actually done conditional loading of templates/ content/ etc.; but I don’t see why the idea wouldn’t work. It’s similar to the process (which I think Chris Coyier has written about) of using js to query screen size/ capabilities/ whatever and setting a cookie with the info, which the browser would then send along with subsequent requests, allowing the server to selectively serve images and other resources.
The idea would work best with a wholly js app (ajax + templating framework —I’m thinking of trying this with polymer, once I get familiar enough with it). The platform capabilities could be queried asap, and would then dictate what content + templates are used.
Anyway… if this concept goes anywhere, you can be sure I’ll share it. But it would be very, very difficult to integrate with WP, if it could be done at all.