Okay so here are all the gender benders I found that you haven't watched
J-drama's: Hana Kimi Special (the 2008 version), Hana Kimi Remake, Ikemen Desu Ne, Ouran High School Host Club (there is also a movie), Mendol
K-drama's: To The Beautiful You, K-POP - The Ultimate Audition, The Painter of the Wind
T-drama's: Hana Kimi
Those are all the ones I could find. Some I have seen and did or didn't like while others I haven't had a chance to see. You may like the ones I didn't like or dislike the ones I liked. So I don't know if my opinion really matters to you. I put K-dramas and T-dramas just because I figured you might be interested in them later.
Another Korean gender bender is Ma Boy however it's a guy dressed up as a girl.