The only thing I can think of is Yue from Magister Negi Magi, who looks and acts like Patchouli...
I'm sure a large majority of us seen this but....
Which came first? Negima or EoSD? I think EoSD came first but they do have a lot of simliarities as it says on the touhou wikia character profile page for PAtchouli.
Patchouli has been rumored to be the inspiration for the character Yue Ayase from the manga Negima! Magister Negi Magi. Like Patchouli, Yue is a short, quiet girl with long purple hair, an unexcitable personality, an affinity for books (she is a librarian) and magic (she is also known to dress in a witch getup similar to Marisa's).
http://touhou.wikia.com/wiki/Patchouli_KnowledgeFunny though when i saw this thread's title. the Yue/Patchy thing was the FIRST thing i thought of like immidiately haha. Seriously.
To be honest though that was the only thing i can think of.
Some things seem to inspire Touhou too.
Like Orin looking like Wendy (the Wendy's restuarant mascot girl) who knows if ZUN likes Wendy's or not or if it was pure coincidence haha.
I do wonder what was really inspired by Touhou though.