I don't think we have "do-able" here, but I found a PVC product from a sign writer (they glue laser cut letters to it) and it works a treat. It too comes in 2400mm x 1200mm (8 x 4 feet) sheets and also comes with a protective layer so your screen stays white and clean until your ready to project
This stuff is about 3mm (1/8th of an inch) think and can be rolled without a problem. I rolled my screen to a diameter of less than 400mm (about 16 inches) to bring it home on the back seat of my car.
It seems to have a slight gain, slightly more than the melamine I've used in the past, but does not hot spot. A friend 's kid couldn't resist touching it, and it wiped clean with no visible trace.
Next I am going to get my local board cutter to cut me a one piece frame for the masking which I will paint flat black. I will then attach the plastic to the back of the MDF using 16mm button head screws...
The screen shot is from SW2 using an entry level SONY HS 3 + DIY 4 prism anamorphic lens + PVC screen