It seems to me that a unit that would play MP3s recorded to MD, and MD themselves would be a hot item. It could also be used to carry data, like many MP3 players. The media is cheaper than the current memory cards. Size of the decoder isn't an issue, MP3 players are quite small. CD manufacturers have made the leap, why not MD?
I understand that ATRAC is a compression method too, but wouldn't MP3 give like quality for less disc space?