This Dandy Gadget: Green-House Japan introduced MP3-player KanaMicro (GH-KANAMR) which has a very compact body.
The Kana-Micro is made in USB flash drive form , which is 55,4 x 20 x 10,5mm and weighs only 10 g. By the way, the device casing is transparent plastic, so you can see all of its innards.
Green House KanaMicro is able to play formats MP3, WMA and WMA DRM.And battery capacity only support until two hours in the playback mode. The music content is stored on a microSD.
It will be available in seven colors, but the price is unknown. [Dandy Gadget Source]