Honestly, now that i listen to records so much, it's hard to listen to mp3's through the same speakers. Not to mention on a mass marketed product aimed at basically non audiophiles.
I think the expectations people have are just too high. I'm not talking about just the OP, i've heard many people on the net who make music complain (but nobody who just listens to music). The philophy of the ipod and every other mp3 player is to basically sacrifice a great deal of soundqualtiy for large amount of storage. So you are taking a device that was meant to sound bad and hoping to make it sound good.
You could try to contact black lion audio or something and see if it's feasable.