I really want some Jyuushiko/Retsu...well, not necessarily porn, but shippy goodness, at least. I mean, I like Ukitake/Unohana as is - their personalities mesh well together - but the genderswap adds a whole new layer to it. Jyuushiko is someone who struggles sometimes with reconciling her strength and her femininity. She's a little bit of a tomboy sometimes, and she had to pose as a boy to gain her strength (well, didn't have to, but she felt she did which is what matters). So she looks up to Retsu, and admires her a lot as someone who does seem to manage balancing being very traditionally feminine with being strong and in charge. And they have a really cute dynamic even just as friends.
I think the fact that the only femmslash I can remember writing is mediocre-to-crappy Tomoyo/Meiling fic that still resides deep in the bowels of FF.net means I should probably do this, though I kind of need to get better at writing Unohana first.