A lot of folks use FR 701 - a type of fabric by Guilford of Maine. There is a website that you can get samples from, but you cannot order from them. www.guilfordofmaine.com
You might be able to ask them if there is a distributor in your area. Or check around the web. Do a search on Guilford of Maine.
BTW, there are other companies that carry that type fabric, too. Wendell is one of them. Again, use your search engine. Good luck!