I'm not sure Dell could ever make a good pda + music player. Their DJ mp3 players were so buggy, they had to release downgrade roms. Same with the Axims. The x30, x50, and x51 regularly crash. Add to the fact that the Intel processors are huge compared to the cheepo processors in ipods and other mp3 players. A true pda with hard drive and the same size screen as a normal pda is going to be too large, too expensive, and have too many buttons.
Might be a cool idea, but I doubt Dell has the seriousness to try to make a stable pda or music player alone.