Temple of Ranma's Sailor Senshi Seifuku

What if one changed the way Orihime Inoue powers worked? Her rejection could be imposing her own version of reality. In canon is said that the only real limit to her powers is what she things is possible. What if that, when Byakuya Kuchiki "Killed" Ichigo the first time, destroying his shinigami powers. Orihime was the first one to find Ichigo? She of course would have tried to heal him, since he was really injured. Now the idea is that since Orihime was desperate to save Ichigo life, she left a heavy imprint in Ichigo spirit, basically changing it. While that would not have been enough to leave any everlasting changes, when Ichigo regained his soul reaper powers, that imprint fused with Ichigo shinigami and Hollow forms...

Things seem to have gone as planed, Ichigo is again a shinigami but... there has been an important change.

Ichigo is now a girl, while Ichigo could fix it, since "She" has not returned to her human body yet, doing so would mean losing the shinigami powers permanently. Being Ichigo, even the treat of being stuck as a girl version of himself with the “assets” of Orihime is not gonna stop her from trying to save Rukia.

Also, not everything is wrong, the soul society is not expecting "her", and both Yoruichi and certain golem girl aren't gonna miss the chance to instruct their new "sister" to to infiltrate soul society. While at the same time Ichigo friends try a parallel rescue attempt to distract the Gotei 13.

How?

The idea is that Orihime reality powers work by imposing her own reality over the TRUE reality. After Byakuya Kuchiki defeated Ichigo, it was the point when Ichigo spirit was as its weakest, Orihime got her powers by being around Ichigo, so her power had a similar enough signature to change Ichigo without much resistance. And since back then Orihime was just using her powers as an instinctual level, and she only wanted Ichigo to live, her will imposed over Ichigo own. Ichigo had a crushing defeat, he not only lost a battle and his powers, but also Rukia, so he barely offered any mental resistance. Last, because Orihime had no clue how her powers worked, the result was her tainting Ichigo “Spiritual Matrix” with Orihime own.

"What changed you was a series of incredible circumstances and coincidences that only happen in badly written fantasy stories. Of course. the fact that one of your friends can warp reality didn't hurt to make it possible."

Seems like a good idea, though it reminds me a tad of http://www.fanfiction.net/s/7998620/1/Overcoming (that I still think needs to be continued) but there need to be more genderswapped bleach fics soo whatever. If need be you could have the change happen after the Ulquiorra fight have it be a a combination of all the times he has gotten healed by her. Have the hollow ichigo reform into a female and when he transforms back to normal just have him stay female.

And if you want to go a tad dark route have the healing alter his mind as well, bringing it more in line with Orihime and she keeps trying to fix it sending farther from the canon mindset.

Upon first reading the title, my interest was not high...

What if one changed the way Orihime Inoue powers worked? Her rejection could be imposing her own version of reality. In canon is said that the only real limit to her powers is what she things is possible. What if that, when Byakuya Kuchiki "Killed" Ichigo the first time, destroying his shinigami powers. Orihime was the first one to find Ichigo? She of course would have tried to heal him, since he was really injured. Now the idea is that since Orihime was desperate to save Ichigo life, she left a heavy imprint in Ichigo spirit, basically changing it. While that would not have been enough to leave any everlasting changes, when Ichigo regained his soul reaper powers, that imprint fused with Ichigo shinigami and Hollow forms...

This however, sounds like fun.

Could also include that the process went slightly the other way as well, Orihime getting partial shinigami ability of some sort? (i always thought she was awfully treated after the first few episodes and after first major arc in particular)

You could also mess with the whole thing, like say, Ichigo´s body becomes male again when he´s not in it.

Or he shifts to female whenever he gets even a little tired(so when he is at his absolute best, his original state reasserts itself, while at all other times, Orihimes "fix" is dominant).