@mental So happy you are enjoying Melody. I have everyone of her albums and like each one. "Worrisome Heart", her debut release is the straightest bluesy jazz of the bunch. After the sophomore "My One and Only Thrill" her releases get a little more experimental as she creates an album-like identity to each one. All fine albums!
If you are looking for another interesting lady vocalist, you might want to give Karen Souza a try. She has a real sultry approach to her vocals. I would recommend "The Complete Collection". It is a three CD release. The first disc is all covers of famous songs. Nobody is out of bounds on that disc. She takes on Strawberry Fields, Billie Jean, Tainted Love etc. She is very different. I really enjoy listening to her when I'm in the mood for something different. Think of it this way...she has unique approaches to songs much in the same way as Patricia Barber.
If you are not into her yet I'd give her a shot first. You might start with "Cafe Blue" the "unmastered" version on SACD if you do SACD. (This is one of the best discs I have for sonics - First frickin' rate!). If not the CD of Cafe Blue should be great.