Super Heroines?

I'm fairly new to the comic scene, so my knowledge is sketchy at best.
There have been lots of films about Superman, and Batman, and Spiderman, as well as the Hulk, and Thor, and Iron Man - I love Robert Downey Jr. as Iron Man - it's his sarcasm and extreme cleverness, I think. I love Captain America, too - he makes me want to hug him, and take him home and feed him home-made apple pie. But where are the films about female superheroes?
Recently, I've been seeing speculation on the web about just that. Joss Whedon wants to make a Wonder Woman film - and it struck me that I don't really know about that many other super-heroines. Or female superheroes. Women, in costume, fighting crime. I thought Black Widow, in Avengers Assemble, was brilliant, and I understand Joss Whedon had to do some arguing to even include her in the picture. I liked her so much that I went looking for the comics, and came across something that combined two of my interests. Paul Cornell, who also writes for Doctor Who, wrote a comic called Black Widow, Deadly Origin - which was an ideal starting point for me, because it included a lot of her back-story and some of the other super-heroes that she had been involved with (including Hercules! Which seemed - well, no more bizarre than Thor and Loki, I suppose)
But who else is there?
I grew up with Lynda Carter, twirling around in her red, white and blue outfit as Wonder Woman, and lassoing people with her lasso of truth - but there doesn't seem to have been a film. All those re-boots of Superman, and not one single Wonder Woman film.
But there must be some more?
I'm vaguely aware that Captain Marvel is a woman now (having originally been a man), but I know nothing else about her.
I understand there are female versions of the Hulk (She-Hulk) and Spiderman (Spiderwoman), there's Supergirl and Batgirl - but are all the female superheroes just pale imitations of a male superhero?
I've heard of Scarlet Witch, and Oracle, but I know next to nothing about them, and they certainly haven't been the subject of a film that I know of.
When I first stumbled across comics, my immediate favourite was Green Arrow, because of the archery - but he had a girlfriend called Black Canary, and I thought she was extremely cool. Not sure about the fishnet tights and blonde wig, but as a character, I thought she was very good.
So, where are the interesting, three dimensional, female superheroes? And why can't there be a film about even one of them?