Let me help Ronan out by giving links to the t-shirt pages:

General Scottish:
http://giftshop.scottishtartans.org/..._scottish.html

Clan Shirts:
http://giftshop.scottishtartans.org/tshirts_clan.html

Humorous shirts:
http://giftshop.scottishtartans.org/tshirts_cheeky.html