> We're shortly adding a "play more tunes by this artist" button, though this works by scanning
> the rest of the current playlist and moving tunes from the current artist to the following play
> positions (trust me, it works)

Ummm...this is a fairly obvious suggestion but what about making new versions of your "play
by year" option that let's you "play by artist," "play by album", or "play by genre?"

yours, Dean