What are the normal Windows OEM ultrabook cycles (new devices)?

I'm very very close to buying the Zenbook Prime from Asus. It is almost perfect. The only thing i'm missing is 8GB of RAM and call me an idiot but i want the new Windows logo on the keyboard :P

So i was thinking, what is the usual time for Asus or other OEMs to bring their new generation of ultrabooks? Is there a third gen "Asus Zenbook Prime UX31A" possible for Q2 this year? That thing is the almost perfect macbook pro/air competitor.