Look at the Flex Steel Magic bed. I have one in my PM. It is fairly comfortable as a sofa and a bed. When it converts to a bed the seam is down the middle giving it a 50/50 split, where as a lot of jack knife beds have a 70/30 split. I believe it is close to 50" wide.
I've been looking online for an extra-wide (63") and preferably taller baby/pet gate for my dog. I want to use this on the front porch and need it to be a tension mounted style..it will be placed between 2 brick columns.