You're asking me to leave out Ella? I really can't answer that. But I'll say, that I really enjoy Diana Krall (not specifically for her scat). But here's an example of it, nonetheless. It's pretty straight forward, unless you factor in that she's completely connected with her piano. No matter where she goes on one instrument she can hold her own with the other, and I think that makes her awesome.
What about Louis Armstrong? He did a lot of scat singing with Ella.