Vash the Stampede's full name is "Valentinez Alkalinella Xifax Sicidabohertz Gumbigobilla Blue Stradivari Talentrent Pierre Andry Charton-Haymoss Ivanovicci Baldeus George Doitzel Kaiser". Now those are some good names to curse my children with!
It is unknown whether his "parents" named him this, or if he made it up himself. This is his real name though, if the anime is to be believed.