We’re a resource guide: we come up with the costume ideas, explain what you’ll need to pull off the look, and provide links to where you can buy the various components.I should be able to come up with something because I'm now the proud proprietor of a small church thrift store.
It would be easy to dress as Mary Wollstonecraft, who published her "Vindication on the Rights of Woman" in 1792. The artwork above shows a neckline that has been back in style, and a ribbon could complete the look, at least on top. If you have a daughter, she could go as Mary Shelley, perhaps with a mini Frankenstein's monster.
Another interesting figure would be Louise Michel, a k a the Red Virgin. With a pea coat and an old nightgown, you could dress as her marching to Versailles after the fall of the 1871 Paris Commune.
I need to stop before I spend all day hunting up costumes on the Internet, but I'd like to hear your suggestions.
ETA: Thanks to Anna for this great link to Violet Socks as well as one explaining how to dress as Joan of Arc.