There would be definite advantages to being able to play two (or more) separate audio tracks simultaneously on an mp3 player. Like listening to an all-talk podcast while playing the ambient soundtracks we all know and love in the background. It would be equivalent to running two sessions of Winamp (or your favorite media player), only on an iPod (or your favorite portable media player), retaining control of each song as you listen to them.

I know you can use ripping / mixing / layering software to concoct something that kinda sorta resembles the above description, but besides taking time and effort and opening the floodgates to the usual quality issues, you would also lose the freedom to adjust the volume / equalizer of one track without changing the other or cycling through one tracklist independently of the other, while you're listening to it on your portable media device, which is really what I'm going for here.

So I guess what it comes down to is I'm asking for mp3 player recommendations. Any suggestions?

Yeah you would have to use a program on your computer first, the mp3 player itself won't do it... itself. Just Buy 2 mp3 players and press play on them at the same time.

Unfortunately, the buy 2 mp3 players idea is probably going to be the best recommendation. What I would do is use a program like Audacity to mix the two tracks together (you can do pan and volume control individually), but you are, of course, stuck with a single stereo mix of the final product. So other than that, I don't know what to tell you, but to the best of my knowledge, there isn't really a better way of doing it.