While Windows 8 inspired plenty of crazy new form factors, it also gave laptop makers a good reason to circle back and tweak their tried-and-true products to bring them into the touch-optimized era. One example is ASUS' Zenbook Prime line of Ultrabooks. We've seen quite a few of them in the last year; the UX31A landed in our offices last summer, and we reviewed the 15-inch UX51Vz mere weeks ago. But a