I am a big fan of ultra portable devices and particularly enjoy using my Fujitsu U810 with long battery life. I just read about the Willcom D4 UMPC over on the CNET Asia Crave blog and have to say this looks like one impressive device. It is one of the first devices running with an Intel Atom processor. Akihabara News was able to get some hands-on time with the device and posted over 80 photos showing it off in all its glory.
The Sharp manufactured D4 device looks like a small HTC Shift with a better display in a smaller prackage. The D4 has a 5 inch 1024x600 display, WiFi, Bluetooth, 1.33 GHz Intel Atom processor, 1 GB RAM, and Windows Vista. It will be interesting to see how this runs with Vista, but I imagine many will "upgrade" it to XP to get better performance from the device.
It is 7.4 inches wide, 3.31 inches deep, and just over 1 inch thick. It weighs just over 1 lb (16.6 ounces) and has a sleek look to it. Unfortunately, this device will only be available in Japan, but then you can probably pick one up from Dynamism in the near future too.