Straddling the line between PDA and UMPC — and ending up looking something like an Atari Lynx — the just-announced Willcom D4, co-created with Sharp, is an Intel Atom-powered computer capable of running Windows Vista. It has a five-inch touchscreen (roughly the size of a whole iPhone or iPod Touch, to give you some idea) and includes to my delight a slide-out QWERTY keyboard. A keyboard that will likely be unusable for long form text input, of course, but one that is essential all the same.
This is exactly the sort of computing device the Japanese used to make more of: sexy little trinkets completely useless for general purpose computing. If it had built-in WWAN or a way to access the internet besides Wi-Fi it could nearly supplant a smartphone. Oh, how'd I'd love to own this tiny computer, leaving it powered off in my bag while I used my full-sized laptop!
The D4 will go on sale in June in Japan for ¥130,000. No North American release dates have been announced.