I want to thank all of you for your comments.
As for framing a large poster, we can shrink wrap frame a poster as large as an Italian 4 foglio. We just shrink wrapped a Batman from 1966 for a client in Toronto. The only hitch is you have to be able to pick it up. I used to think this was only a service for collectors in the Greater Toronto Area, but we shrink wrap framed two 3 sheets for a client in Maryland and he drove up here and picked them up. We also shrink wrap framed 12 one sheets for a client in New York City and he drove up and picked them up.
As far as I know, we are the only firm in North America offering shrink wrap framing and it is a hell of a lot cheaper than standard frames, they are durable, and perhaps most importantly for the large posters, they are lite.
I tried to attach a photo of the Batman shrink wrapped, but I haven't mastered that yet. Email me and I will send the photo... backingtothefuture@gmail.com.
Cheers, Dan Miles, Backingtothefuture.