Actually, before I found a jacket I could alter at the good will, my friend suggested getting an actual Japanese school uniform from somewhere and altering it. That may be an option for you. Or, if you can find a pattern somewhere for a uniform, that might work, too.
__________________ "Here's another curse: May all your bacon burn."
Future Cons: Anime Expo 2013 (L.A)
100%: Yosuke Hanamura (Many outfits) (Persona 4)
Possible Future Projects:
Chie Satonaka (Persona 4)
Korra (Avatar: Legend of Korra)
Past cosplays --> My ACParadise profile
I would have just altered a regular pattern for a long jacket to the way it looks like for the uniform if I had to make one. But I'm pretty sure there are some places that has free patterns of Japanese school uniforms. There are free ones for sailor fukus.
__________________ my upcoming 2013/2014 Cosplays
Quina (FFIX), Kat (Gravity Rush), Nausicaš (Nausicaš of the Valley of the Wind)?, Zhang Chunhua (Dynasty Warriors 8), Mii Kouryuuji (Project X Zone), Mami Tomoe (Puella Magi Madoka Magica), Shushou (12 Kingdoms)?, Cheria (Tales of Graces)
Next cons: Katsucon, Anime Detour, Fanime, Anime Central, Anime Expo, and Midoricon. Cosplayer and photographer. Follow me at my DA, twitter, or my tumblr!