Will we ever see a good, big-budget Superhero movie with a female protagonist?

I was watching the trailer for “The Avengers” today, and thinking about how well Scarlett Johansson does in her superhero role. I realized 4 of the main characters in that movie have their own, well produced, well written movies. I never expect to see a “Black Widow” film released. After further thinking, I realized I have never seen a good superhero movie with a female protagonist.

Would you watch a good superhero movie with a female protagonist? Do you think there is a demand that would ever draw enough fans to justify a decent budget? Do the good writers just not bother?