I appreciate you not including the likes of Rihanna, Katy, and Kesha. Singles artists do not receive Platinum certifications and sell 2 million+ internationally.
Anyway, my votes goes to Shontelle. I've always wanted her to blow up because she's extremely talented both in songwriting and singing, she's got tons of star potential, and her music is high-quality. She even takes the time out of her day to respond to her fans on Facebook/Twitter. I've communicated with her multiple times and I have multiple copies of both of her albums. I just want her to happen but I doubt it'll ever happen. Excuse me, I'm getting emotional.
I think Kristinia is cute, too and Keri's albums are very great and underrated. Keri simply can't sell, but Shontelle and Kristinia have no label support.
Well, a lot of them dream of getting multiple top 40s. They'd just be satisfied with one. 
