Philbo; There is a registry in Scotland, I think it's Tartan Registry, that will research any tartan you create and if it is not similar to any other tartan registered they will register it as an official tartan. That is how most city, state providence, and group tartans are done. Or, you can simply create and use one on your own. there is a web site out there some where that will help you create a tartan also. Sorry I can't remember the address or name though. To steal a phrase, "Just do it"