The Toshiba SS MXW—they didn't want to add TOO many meaningless letters after the name so they stopped with five—is an Intel Core Duo T2300 laptop running at about 1.6-GHz with up to 1GB of memory. It has a 12.1-inch display and weighs a mere 4.2-pounds. Built-in WiFi and a card reader are nice, too, and size seems just about right. It'll be about $1,500 if or when it reaches these shores, but you can buy it in Japan right now.
Product Page [Toshiba via TechEBlog]