Yes Badger the Fjord was called Lucus (and still is on his passport), he didnt know his name though as came from a dealer over from Sweden. Lucus just does not suit him, he is too cute.
I'm pretty sure I'd change a horse's name if I didn't like it. I wish I'd changed Leah's name when we got her, because I'm not too keen on it (people always think she's a boy dog called Liam or Leo!), and obviously by the time I realised it was annoying it was too late!
On an vaguely related note, the lady I used to help with her ponies said I could name her new colt foal and I said "well, he looks like a Romeo to me" to which she replied "hmm, yeah. What's the Beckhams' other son called again?". I nearly cried.
We bought horse via loaner who called her tatty and her show name was little miss tatty bag (loaners sense of humour).I didnt find out until I had bought her that her name was Millie but we had been calling her Tatty and its stuck.
She doesnt look tatty anymore and has really filled out so feel a bit mean sometimes lol
we got some awful names at work... one called muppet, i begged them to change it to muffet and another one called monkey again i begged them to change to mickey but there certain its bad luck... i did change a name from red to blue, had loadsa bad luck with him! but on the other hand kept on called tequila the same had had bad luck with her!!! worse name i had was pimple but didnt change it and never had bad luck!
Genie's name was changed by the people who had her before me. She became Miss Congeniality (Genie), and before was Scooter! Their reasoning was that Scooter is more of a boy's name.