Testers would be great ... I just finished connecting to the empeg, downloading the database, and rendering a Swing tree out of the playlists. (This probably doesn't sound like too much, but it took quite a bit to get that far -- it's kind of cool to see it working). The nastiest part by far is the endianness and type conversion... I can't tell you how many times I've screwed that up.
I'm pretty scared to test some of this stuff, because if I screw up the database rebuilding stuff, I'm sure I'll hose my empeg all up...
But anyway -- Once I finish implementing ConsoleInterface (so you can navigate around the player), I'll put a build out on OpenEmpeg and let you know.