Actually, I DID have a project for that! This one period history au wherein Tezuka was a Samurai (injured from pushing his shoulder too far!) and Fuji was a well-off merchant's son who had dealt with accusations of treason and a sickness wracking his body. I think I wanted to do a SanaYuki part too? It ended with a reincarnation epilogue. I never wrote it because my attempt at researching it brought up very little helpful material so I just sort of dropped it *shrug*

Well, I think a non-Tennis-playing Tezuka has lost a bit of himself, even if it's not pro. So Fuji sticks by him and they have hot hurt/comfort sex heal together that way.