Advanced piano sheet music for musical theater

[davidrussell]

I’m an advanced amateur (30+ years). Recently I’ve started accompanying a singer who does musical theater. I just got the "Great American Songbook - Broadway" by Hal Leonard, and while the arrangements are pretty good, I was a little disappointed to find that every piano part has the vocal line written into it. I understand that this can be helpful for singers who are learning, but it seems rather unprofessional to me.

Where do people go to find high-level piano sheet music to accompany singers of musical theater? I think the ideal is basically a transcription of the orchestra/band part, without the vocal line written into it (unless it’s mirrored in the instrumental parts, of course). If it matters, the song I’m interested in right now is from West Side Story.