Panasonic has announced 3 products:

the D-Snap SV-SD750V/700 (87.3x46x11mm and 48.4g) and the SV-SD350V/300 (87×40.5×10.3mm and 47.9g) are MP3 players with an FM tuner and these machine work on SD cards. Battery life should be at least 45 hours, but that can be raised to 94 or 105 hours by using an additional battery… coooool!

Then we have that mini HiFi set, the SC-SX800, that also has an SD card slot (to be compatible with the MP3 players) AND a 80Gb HDD to store your CD’s onto.