Fujitsu has come out with a 400GB version of their “handy drive” portable 2.5″ hard drive.
This thing is about 5.6″ x 3.3″ x 0.9″, weighs 9oz and gets it power through it’s USB 2.0 connector. What’s the downside? it’s only a 4200rpm drive: usable for backups not so good for something you access regularly.
It’s out in Japan now for about $335.