Are a lot of butlers named "Sebastian"? In Lucky Star, Konata calls Shiraishi, one of her classmates (and co-host of Lucky Channellu), Sebastian, apparently because he looks like a stereotypical butler. This is presumably an anime/manga reference. Any idea where this reference comes from? Are butlers in a number of anime called Sebastian?
Seemingly that particular scene is referring to Mara Mite, or Maria-sama ga Miteru as Konata was parodying one of the main characters - Sachiko Ogasawara.

Reference

But in general, Sebastian is a stereotypical name for a butler in anime, and this fact is often used in comedic scenes involving them:

In Sayonara Zetsubou Sensei Fukka insists on calling the Itoshiki families' butler Sebastian, even though that's not his name. Similar scenes occur in Junjou Romantica, Paradise Kiss and Mayoi Neko Overrun where butlers have the name forced upon them

It occurs in western media too, although Jeeves tends to be the name of choice, and appears in media over here in a similar sense. This first occurred in P.G. Woodhouses' short stories and novels and inspired similar characters. Presumably the anime trope surfaced in a similar fashion.

In P.G. Woodhouses' stories, there is also a butler called Sebastian Beach, this could be just a coincidence though.

When I was looking information up on this, Black Butler and its Sebastian Michaelis kept cropping up, the name Sebastian here serves two purposes - the stereotypical butler and also sharing the name with a historic figure http://en.wikipedia.org/wiki/Sebastian_Michaeli