Krusty the clown? Needs to have daddy issues - maybe Thaddeus Sholto from "Sign of Four"? I want to know who Mr Burns would be.

I've just remembered about Cross-Dressing!Holmes (I'm re-reading the canon and can't for the life of me remember which story it's from - or if I'm making this up!)

He's notorious for being good at putting on disguises so I bet he's got a collection of hats for: Groom!Holmes, Opium Den!Holmes etc. etc. :)