NVIDIA Optimus graphics, and a four-cell battery that promises ten hours of battery life -- all of which comes wrapped in a 0.75-inch magnesium shell that's apparently available in your choice of black or silver. Unfortunately, all other details, including the screen size (though 13.3-inch seems likely), remain a bit of a mystery, as does the pricing and launch details.
Update: We've come across a couple of Taiwanese listings for the U36 spilling the full specs: 13.3-inch LED-backlit screen, Intel Core i5-460M CPU, NVIDIA GeForce 310M graphics with 1GB of memory, 2GB of system RAM, a 500GB 7200RPM hard disk, HDMI output, one USB 3.0 port, a 1.66kg weight, and Windows 7 Home Premium as the OS. Pricing is less reliable, but we've seen a top MSRP of NT$41,900 ($1,375), which has invariably been discounted by local retailers to saner levels. Let's just wait and see how things turn out when the U36 makes its way westward.
Update 2: ASUS just informed us that the MSRP for this model in the US will be $999, and that it's expected to arrive in about three weeks. At least some retailers are already taking pre-orders, and an Amazon listing is said to be coming "shortly."