The search results with the User: pages on Wikipedia turn up a fair number of historians of science, mostly graduate students and professors (and there are probably more who don’t mention their field on user pages). Check it:
Shleep
BWOgilvie
Wujastyk
AppleRaven
Neale Monks
Mollyclare
Xuanwu
Fastfission
Pfaff9
ABVR
On a related note, I’m starting a WikiProject for history of science. If you’re a Wikipedian (or would like to become one), you should join it.