Look up Lara Price Band. They are more blues than alt but sooooo good!!! The lead guitarist is Laura Chavez and she TOTALLY steals the show!! Please, everyone that reads this, Google her, she is definitely a force to be reckoned with in the up & coming lead guitarists.
And, so, but... My fav alt chick is Natalie Merchant. With or w/out the 10,000 Maniacs