I am in the U.K. and use a local framer, who will do what ever you want. A full archival frame for a Quad is around £70 all in with Plexi.
Difficult to word this, but I find if hanging a poster over a Radiator, put a shelf above the Rad, and it will deflect most of the heat away from the poster, and into the room. Don't forget Radiators don't Radiate (much) heat they convect....
If I find a pic of mine I'll post it.