The VIA NanoBook is powered by the ultra low voltage 1.2GHz VIA C7-M processor and delivers up to 5 hours of battery life. Powered by a choice of Microsoft Windows XP or Windows Vista Basic operating systems, it comes with host of advanced features, including a full keyboard, a crisp 7" WVGA screen with touch panel, up to 1GB DDR2 SDRAM, and a minimum 30GB HDD, as well as 802.11g WiFi, Bluetooth and Ethernet support, plus a DVI and two USB 2.0 ports.
Even such, UMDs are becoming more common as in-between for PDAs and laptops, where more desktop or mobile applications are required but beefy hardware is not. The units also will feature a touch screen and a card reader, making them ideal for very-portable field work.
They are slated for introduction in the second half of this year. You can read more about the NanoBook UMD reference at Via's site. Personally, I would much rather see vendors push for 5, 6, 8 or even 10 hour battery life notebooks before pushing performance even further.