More on Longest Name Ever:
I'm told its number 33 on the Celt building list. http://forums.civfanatics.com/showthread.php?t=485816&page=2
The Huns borrow from all civs city lists, so there may be a chance of getting it when playing them, but I don't know.
Thanks, I checked the XML files in the game, and you are right. It is the 33rd city. I'll update the guide. Not sure about recommending the Huns though, because the chances of picking that city name don't seem likely. Too much of a long shot.
And, of course,
[1] the name used in Civ5 is only about half as long as the actual name of the Welsh city, and
[2] according to Wikipedia, there is a Maori city in New Zealand with an even longer name....
See the pop-culture reference section. It already says the full city name and mentioned the New Zealand city.