Female Vocalist like Diana Krall, Jacintha.

Perhaps it's something you already know about, but there's a long running forum on AudiogoN called "Best female vocals on CD." Lots of suggestions and loads of reviews.

Karla Bonoff. Not a weak cut on any of her albums. These aren't audiophile recordings but plain, good music. Writes most of her own music too. Going to see her live for the first time Friday night in an intimate, nearly perfect acoustical venue. I can't wait.

Try Lizz Wrigth, her album Salt is out on Verve.

Not sure if she fits in with your description, but I think that Jennifer Warnes is very much under rated with a superb voice. Most will cite "Famous Blue Raincoat" as her definitive album. However, I personally think that "Shot Through the Heart" and "Hunter" are both superior albums in terms of content, if not sonics.

Try also try, Marlena Shaw "Live in Tokyo" on Eighty-Eights, a Japanese pressing, of you can find it. Maybe it is on CD, too, I don't know.

I like Eva Cassidy, as well. Also, Janis Ian "Between the Lines" and "Breaking Silence".

Have you tried Dinah Washington?

Ella Fitzgerald, simply the best.