Having mentioned the Real Group, herewith a sample of their work
http://www.youtube.com/watch?v=jXtpiEaQKcc
How do you classify that? Vocal Jazz? Voices as instruments?
Regardless of classification to me it's part of jazz and I like it.
As for Lambert Hendricks and Ross, again jazz to my mind, but a different approach, lyrics set to jazz numbers, example
http://www.youtube.com/watch?v=8Vyxf...eature=related
Discuss!