I think the Empeg player is the best mobile mp3 player on the market today. I want to buy one but what's stopping me right now is what I perceive as incomplete playback flexibility. On my PC I use MusicMatch to organize my mp3s and I would like the equivalent playback flexibility on the Empeg.

Let me illustrate what I want by a real example. Currently in MusicMatch I organize my mp3s by album, artist, title, genre and tempo. MusicMatch has an AutoDJ function which lets me specify conditions on these fields after which it will randomly play songs that fit my criteria. For instance I could select all songs in which genre=rock and tempo=fast. Or I could select all songs in which genre=dance or reggae and tempo=fast or moderate. Of course due to the limitations of ID3 the empeg will not support tags such as tempo but this can be accomplished by nested playlists. Therefore on the empeg car I should be able to choose one or more (nested) playlists and have all songs that match the criteria be played. Note that the choice should drilldown not only through the nested playlists but also to the ID3 tags.

When I start up my Empeg then I should be able to specify something like the following:
Fast/Rock
Moderate/Rock
Fast/Reggae
Moderate/Alanis Morrisette

After this choice I should be able to hit play and then hear randomly selected tracks matching the above criteria.

I am not going to presume to specify how the above behaviour should be implemented. However any solution that gives the above playback functionality would be acceptable

Regards
Lester