Kohran Ri from Sakura Wars / Taisen.
When I was at a con two years ago I was just wearing my purple wig. I was too lazy to take it off after I took the costume off which wasn't tailored yet. Anywoo, while I was in the dealers room someone thought I was Revy. I would defiantely suggest that character if you're familiar with the series.
The only thing you would have to do is braid the wig into 2 pigtails.
Here's the character. http://www.sakurawarsdvd.com/images/...n/kohran01.gif
And me cosplaying her for wig comparison, I dunno what style or exact color your wig is so I'll just show you what I used.
Good luck in your search!