I think I can rig one up using dowels and a clamp to hold the screw that tightens the frame. I'd need wood glue, a flat piece of wood that's had the hell sanded out of it, a couple screws, a piece of dowel, a clamp and a power drill. I think I'd be maybe five dollars out of pocket in the end. Maybe more if I grab a bracket to brace it well.

I'm really kind of surprised by how often I've used power tools in costuming.