I'm not too familiar, but doesn't Putting it Together have a few good 4 person songs? I think you're right about Millie, too, Aigoo. Although I can't think of many 4 part harmonies, just songs with four parts. That's the tricky part...
I hold a degree in Musical Theatre from Montclair State University. It is useless. Now I'm funny for money. Oh, and I sing.