I've always thought that we should have some way of tracking which player owns which character, either within the guild interface, or within the game at large -- though people probably have privacy concerns about that, it's interesting to me to see people playing different alts and how they act differently. But theme names are one way of showing that characters are all part of a larger group, without actually revealing those ties to anyone not in the know. It's a cool idea -- almost makes me wish I'd put a little more thought into my characters when starting out.
So: do you have a theme behind the names of your characters? Did you plan it out or did it just happen? And is it clear (they all have the same root) or is the theme known only to you? What, if any, are the ties between the names of your different characters?