Try Ruffin Flag Company, in Washington, Georgia, almost within rock throwing distance of Robert Toombs home. They are on line, just Google in Ruffin Flag Company and it will come up. They have some toll free #'s if you want to check their inventory, but I know they have every State flag in stock in 3 X 5, either nylon or cotton, and can get larger sizes, if not in stock. They specialize in histoic flags, and can furnish any number of Confederate flags -- first national, second national, naval jack, Stainless banner, etc., etc.
Before they moved to larger quarters, they were literally across the street from Alexander Stephens' home in Crawfordville, Georgia. Good roots.
The toll free #'s in the on line site are (888) 884-3524 & (866)882-8269. It appears their on line site is firstname.lastname@example.org.