Keep digging - Though the majority of Irish tartans are alligned with geographic entities, there are some irish names that have tartans of their own. A few examples - Doyle, O'Rourke, Down, Forde. Here is a link that might interest you - http://www.scotchcorner.com/mill-text/irish-index.html

I am sure there are others the more experienced members could point you to.

And - irish, scot, breton - all celts - and surely linked by blood some time in the ancient past.