Very interesting stuff, a subject that I too am quite interested in!

It's not so difficult to crossfade on a PC platform, resourses allow two decoders to play at different rates and the output to be mixed, I've done it in windows!

Not sure how easy it would be on the Empeg, you need processing power but also you need ram to buffer both streams and you need to pre-analise the beginning-end of each track to calculate BPM (Beats Per Minute) and work out syncronise positions!

Possible, but a little tricky to squeeze into a machine that is already performing miricles! I guess it will take a really good programmer with plenty of time on their hands to stand a chance of getting done!

Just my thoughts ;-)