Fabric Depot in Portland carries a huge line of repro fabric. Usually the word repro offends me but I actually have some Civil War squares and went to FD to match it up so I can put them all together. They don't offer much online but here are a few on sale now....you can email them, also, and they may help you find colors.
http://www.fabricdepot.com/index.php...ng=civil%20war