I was just thinking about my wedding (that has been put on the back burner due to circumstances) and I remember mine.
My DPs DM and D(aunt) are from a different country but have lived in England most their lives. Where they come from it is customary for the grooms DM to give him away at his wedding. My DP expressed he would have liked his DM and his DA(unt) to walk him down to the altar as they both raised him and his DA is like a second mum to him and has no DCs of her own. I thought it was a lovely idea especially since it was something from MILs culture.
Upon discussing a few plans with my DM and telling her what DP will do she went away and came back announcing that she would like to give me away with DF(ather) as she thought it would be lovely etc
My DF (who usually goes along with her demands) was even 
- for the record judging by her character I believe my DM just wanted to do this to basically go "look at me I'm such a good DM my DD wanted me to walk her down the aisle at her wedding" and it seemed like a game of one upmanship because of what MIL got to do.
I'm sure I have some more examples goes digging in memory.
Has anyone got any similar stories of weird requests?