This place always has a great supply of themed paper. The link I sent for for their wild west products, but if you do a search on "western" they have some other styles too. Good Luck!!

Brochures, Business Stationery, Invitations and Award Certificates - PaperDirect

Sincerely,
Krista
Wedding, Bridal & Baby Shower Table Cards, Place Cards, Favor Tags, Note Cards, and Programs