How big is big...3 x 5 feet could be framed like a giant piece of art...with the mirror serving the glass role of photo mount. Another option is to mount the mirror to the wall then apply a "frame" of moldings around it.
How about a mirror mate? http://www.hometalk.com/member/mirrormate
I will use both suggestions and I'll post picture after it is done. Thank you very much.