How to display an antique crochet?

We have a family heirloom crochet piece (large... almost 3 foot tall by 6 foot wide) and want to frame it so we can display it without worring about damage. My local frame shops say they cannot get archival quality matboard that wide so if they mount it there will be a noticable seem in the middle. So, I began researching and learned how to "couch" by sewing around the key points of the patterns and thought I'd buy acid-free fade/bleed resistant cloth to sew to and mount that to a pieced together foamboard to have no seams. I have not been able to find such a fabric after nearly a month of searching. To make matters complicated, the room where we want to hang it has a burgandy color scheme, so we are looking for a burgandy fade/bleed resistant fabric. I am confident we can get the frame built and have a source for the uv blocking gl, however, I cannot find the fabric. Does such a thing exist or am I going down a wrong path? What should I do to preserve this and display it?