Not quite in the genderswitch broken-spine category but perhaps interesting, and I shall have to describe this from memory as the example is pre-internet:
Slash illustrations in the bad old days, before photomanips and manga, tended to be heavily modeled on m/f couple poses. This meant that one member of a slashy clinch was likely to be in the "adoring clingy" role or the "take me now Rhett" pose, as the case might be. My un-favorite of all was something clearly based on an underwear ad, where Slash Hero Coverboy was coyly hiking up his tee shirt to display the waistband detail of his boxers.

Not that the sheer pulchritudinous excess of comics doesn't have that beat, becuase it does. However, fandom has been genderbending in bad as well as good ways for a *long* time.