I'm really sorry for bringin' up such an old thread, but this is a really great idea. This could be a nice adding to the search-function. To be able to search for several, say artists, or songs or whatever. Immediately when I read the post I thought of searching Nile + Behemoth (two of my favorite bands), which -if it had worked- would have brought up all tracks by these two bands. This would be a nice way to make a fast playlist, for example. This could be useful in so many ways.