I second Ranma 1/2, it's definitely got the gender-bending, people falling in love with both versions thing. Also if you like that, you could check out The Changelings although this may not meet all your specifications.
Hope this was helpful!

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I give up. I see not point in living if I can't be beautiful.

It had been hard to remember this manga name Kashimashi - Girl Meets Girl, the more fit I can find. To me it was pretty meh, I dropped it, so take your chances.

Wow, so many suggestion.
I've finished reading Mizuho Ambivalent. I like it. Almost perfect fit with what I want. If only the MC has triangle love with the Twin, now that would add more Spice.
Im taking a little break by reading Region.
All those Trap are dangerous.
Next, Im gonna read Yubisaki Milk Tea because of vague memory.
Then Kashimashi - Girl Meets Girl and maybe The Change! too.
Sekainohate de Aimashou would be the next.
That is if my plan is going according to plan.

Status Update;
I've already finish reading Pretty Face, Tenshi na Konamaiki & Ranma 1/2 quite a long time ago.
Since Ame Nochi Hare (Bikke), Dress na Boku ga Yangotonaki Katagata no Kateikyoushi-sama na Kudan, Sekainohate de Aimashou and AKB49 - Renai Kinshi Jourei aren't "completed" yet, Im not gonna start reading it yet.
But recently I've finished reading Prunus Girl, Mizuho Ambivalent, Mint na Bokura, No Bra, The Changelings, Kashimashi - Girl Meets Girl & Yubisaki Milk Tea. And Im very satisfied with most of them. Very almost fulfilling with what Im looking for. Thank you so much guys/girls for all the suggestion.
Now, is there any other suggestion for me to tackle next?

Have you tried Nicoichi? They're grown people but I think it fits your description enough

Last edited by iine at 12:23 am, Dec 30 2013

What about Joshi Mousou Shoukougun or Ai o Utau Yori Ore ni Oborero! the only difference is that in both of these the girl also looks like a guy, and girls are always fawning over her, and the guy looks like a girl who has guys fawning over him.

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If you have to raise your voice to improve your argument, it merely shows how weak the ground you stand on is.

Nicoichi & Joshi Mousou Shoukougun are already in my "Gonna Read" List. The problem is, they both are still "incomplete", therefore I didnt start reading them yet because I dont want to read, stop for I dont know yet how long, and then continue reading later but already forgot the stories that would make me reading all the way from the start again. Might as well wait unpatienly till its all ready.
Thank you for the suggestion.
So next Im gonna check on Ai o Utau Yori Ore ni Oborero!.