Not only can this 2007 model UX490 quad-boot into OS X, Windows 7, XP Pro, and Vista Business, but its specs have been overhauled. A voice-capable HSPA modem has been added, plus a faster CPU and larger solid-state hard disk.
The original 1.2GHz Core 2 Solo U2200 processor (which was soldered in place) has been swapped with a 1.33GHz Core 2 Duo overclocked to 1.438GHz. And the 48GB SSD is replaced with a fast RunCore ProIV 128GB SSD. Amazingly, the battery life is said to be pretty much the same.
It's a pretty involved mod, but it's a hackintosh I'd definitely like to take for a spin. That 4.5-inch touchscreen doesn't look too bad, either.