Well, first off, there *is* at least one alternative player for the empeg that's shown some promise. It's called Squash, and it's pretty darn good for what's basically one guy's hobby. Do a BBS search for some info. It's still got some UI work to go, and the overall design is definitely a departure from what the empeg has (it's more geared towards intelligent shuffle playback than any kind of ability to select specific songs, though the author's told me he plans on adding that in the future.) Installing squash is definitely not for the faint of heart, be warned.
However, the reason many people (including myself) lust after the empeg player app's source is that, for many of us, it's *almost* perfect, but we'd like to add stuff. If we start from scratch, or even just string together a bunch of 3rd party libraries and a cheesy UI, we've got a long way to before we get to something as rock-solid and featured as the empeg player app.
So what would we do with it? Well, that's hard to say, but there's a pile of often-requested features over in the Wish List forum that, more than likely, won't ever get a chance to see the light of day. The guys at Cambridge are too busy, you know, providing for themselves and their families. They like the empeg community, but it's not hard to understand why they want to work on things that keep themselves employed.
But if we had the ability to code in our own extensions, plugins, etc. into the player app, I think it'd open up a whole new world. As evidenced by the Hijack kernel, along with a few of the apps people have written, it's possible to add neat functionality to the empeg without having the player source code available. But there are a lot of things that we just can't get at.
As for the XML-based custom info modes, my thinking behind using config.ini was that it's already available, and easily edited from emplode. I'm not totally ruling out XML for a future release (as long as I can find a lean, efficient, and free XML parser written in C) but for the next release (hopefully in a week or two) it'll still be a matter of adding lines to config.ini. But I'll add XML support to my wish list.