heat bending acrylic or polycarbonate isn't as hard as it seems. You can generate enough heat with a bank of heat lamps or infra red elements like the ones used at auto body shops to cure paint. There are a number of ways to make a quick buck to drape the plastic over.
Even a couple of these would do the trick, then when you're done bending you can heat your patio with it:
Heaters | Patio | Solaira Infrared Heaters - GlobalIndustrial.com