We DO have 1 tartan (we're currently out, but I can get more) that we affectionately called "the Guiness Tartan". It is NOT associated with Guiness, but it was Black with 2 Tan bars and a thin Red Stripe. There's a pic of it on our "Pictures" page. 2nd row all the way on the left. Guy with the guitar has it on. Not a great pic, but it gives you an idea...

http://www.usakilts.com/pictures.htm