I'm kind of surprised you can bend PVC pipe without having it break. I do like your portable frame, I am thinking about using a leaky plastic stock water tank to build a raised bed. When I was a kid up North, people made what they called "Hot houses" to start their plants early. They uses fresh horse manure on the bottom to generate heat,and topped it with soil, and covered them with windows that they had build into a frame. I wondered if I put fresh manure on the bottom, and soil on top, and then a plastic cover like yours on top if that would work. I might have to give that a try.
