I made a large table with sweep using 4'x8' acrylic. I used acrylic that had one side frosted, and placed the frosted side down. I used a heat gun to bend the sweep. The front sweep was kept in place by attaching a 1"x2" firring strip (wood) underneath the front edge, secured to the acrylic by bolts and washers. This strip was then secured to the bottom of the main frame structure by using picture hanging wire, i.e. guy wires to keep the sweep taut.
With this setup I was able to photograph fairly large objects. I used coloured paper behind the surface to change the background colour. This way I didn't have to use gels on lighting equipment, and IMO the background colours were better. Lighting the background paper from below allowed me to photograph objects that appeared to float in space. I could also simply place background paper on top of the sweep if that was better for the subject.