The aluminum tubing idea talked about in this
thread may be helpful for making a stand.
I assume you would want to attach the BO cloth with Velcro.
Maybe you could get away with just using more styrofoam and Velcro. Cut the styrofoam in equal sized rectangles and lay one layer horizontally and the other vertically and attach the two layers with Velcro. Attaching the Velcro to the styrofoam would be the trick. If the Velcro doesn't attach easily to the styrofoam, maybe attaching some other light medium to the styrofoam would then allow attaching the Velcro to that light medium. The layers of styrofoam may make it sturdy enough to not require additional framing.