I know a fifth-grader (female) who has a strong aversion to wearing skirts and dresses. Her school is holding a "colonial period dress-up day" where they are expected to come in costume. I thought that a great solution would be to show that there have been a handful of non-conformists throughout history and to come dressed as a specific example of a woman from that period who wore trousers. Can anyone point me to an example?
The number of women in history who wore trousers specifically as a protest is vanishingly small (most non-conforming women were more concerned with legal and social rights denied to them than clothing), and none that I know of lived in 17th or 18th century America. Your better bet is to have her dress as a woman who lived as a man during the Revolution - Deborah Sampson (1760-1827) is, I believe, the only known woman who disguised herself and enlisted, although it's of course possible that there were others who were never detected.
Otherwise, she could simply dress in male clothing and tell anybody who asks why she isn't wearing a gown that she didn't want to. For a dress-up day in elementary school, there's no need for justification.
Try Anne Bonny, an Irish-American pirate and Calico Jack's lover.