I'm being more active in Mandrake Cooker development... at the moment, I'm hacking out something I'm surprised no one's done yet: an xmms output plugin for libao2. The main benefit for this is that libao2 supports (among other sound output systems) OSS, ALSA, EsounD, and aRts, automatically detecting which to use. This is nifty for use in distributions that support both KDE and GNOME as a default xmms output plugin. At the moment, it can play audio and in general behave like a nice xmms-plugin. Effect plugins are the only TODO before I release and upload it to contribs (which I should have write access to shortly... ;o) ).
Beyond that release, the only thing I can see me implementing is support for volume control... I may just do that in software; making hardware calls just seems yucky for a hardware-independent library. I've also noticed (of course, I could be wrong... I haven't checked code or anything...) that the EsounD output plugin doesn't support the xmms EQ, so that may be a TODO. I may add some rudimentary prebuffering support into the plugin, as it looks like effect support may add enough overhead to make that worthwhile.