history and previous is kind of the same thing no?
not really any room to add 5 more buttons on the audio screen, but there are 5 buttons for each playlist stored on the plist screen, top row, so its only 1 click away from the audio screen (for now).
as for the feature, ive allready begun to convert it to be history based.
The cool thing is, i only needed to write a few lines of rrcode and everything else is left untouched, so its possible to make this an option. But the default i believe will be history.