I realise this is probably crazy talk, but has anyone considered attempting to integrate musicip mixer into rockbox (
http://www.musicip.com/mixer/index.jsp )
For those that haven't heard of it, musicip mixer is essentially a playlist generator that acoustically analyses your music library and allows you to generate a playlist that sounds like / is based on a seed song of your selection. In a cruisy mood? Generate a playlist basd on just about any Jack Johnson song and you'll be asleep in no time. In a cruisy mood but want to work your way into the evening? Set your seed song as a Jack Johnson number and your end song as AC/DC and let musicip work out everything in between.
It doesn't work 100% perfectly, but it gets things right more often than not, and exposes me to a lot more of my music than I play by myself. I've found my Squeezebox Duet and musicip plugin have changed the way I listen to music.
Now, I'm a dunce, so it is probably laughably impossible, but I just thought i'd throw the idea out there to see if anyone has considered integrating musicip with rockbox...?
PS I've no affiliation with either musicip or squeezebox beyond being a satisfied user of both.