There are mp3blaster (which I haven't got to work) and mpg321 (never tried that) in the feed, maybe try one of those? As for comfortable usage, maybe you could write an opie-sh script, shouldn't be too complicated...
Cheers
Philipp
P.S.: You could also check the OpenEmbedded build environment and build an xmms for yourself, maybe you can get rid of the opie dependency, or just build nmf yourself...
Edit: Ok, come to think about it, since you run gpe, opie-sh might not be the right idea *G*