Yes, already passed my mind too, there are some similarities that can be explored by current PDFE architecture. Even embedded images extraction is possible, and the PDF Veiew tabsheet can be used to present a MP3 player.
But, them I think, PDFE is not well-adapted to deal with some of theses specific MP3 metadata fields. I really don't have a good idea on how to deal with formats that have standard metadata fields diferent from the ones already in use by PDFE.
There is always the possibility to extract these different metatags to PDFE custom ones, and then use a MP3 specific grid layout to show them. But this will work only if user is forced to use this grid layout to deal with MP3, and I really don't know if it is the best way go with. Any idea?