I saw someone advertising one once, I think they pretty much just put together one half thought out story, then charged people money to name the existing characters in the story after them and add a note about their species and outfit.

...

On one hand I want to hate the guy, on the other hand I wonder how much my integrity would suffer if I could make $50 off one 5 page story. (Note guessing at the length of story and final profits as I couldn't be bothered to actually investigate further)

Heh, curious myself then too. Wonder if anyone bought it.

No idea, I take exception to the idea a YCH story could be done in such a way in that it seems like it would completely fail to capture the characterization of the person's character and how they would uniquely react.

I suppose it would be possible to do it in a sort of way, where you say 'okay this is a story about your character who encounters x which turns them into y. Sign up if you want your character to be the main character and tell me about their personality' and then write the entire thing from scratch based on how it would work with that character...

And at that point it's basically a commission with a pitched topic.

I kinda did something like that, once upon a time! It was a haunted house themed story from Halloween of, like, 2013? Long time ago. There were 9 rooms that would have things happen in them, and people got to buy in to have their character get caught up in that room. Not entirely a YHC, but about as close as I've ever come with a commission.