I'm not sure of the exact correspondence of touch screens to @media query recognition, but you can target more advanced smart phones with CSS @media rules, so that might be the answer to your need here.
On the horizon, we will soon be able to detect all sorts of things, like how much bandwidth the device is currently supporting and how much charge its battery has. So presumably there will be ways of detecting if there is touch functionality, too (if not already). It just may not be necessary for what you want to do here. CSS3 is the easy way.
Had this post open for longer than I realized. Lots of answers posted in the mean time, so this may not be relevant.