I've been watching a lot of tubing bending videos lately too - my 16x20 high tunnel is going to need to be recovered within a couple of years and I want to replace the PVC structure that we used for the top with either EMT or the chain-link fence posts - which seem to be kind of surprisingly easy to bend using a hoop bender.
CaptObvious, I think I would lean toward the electrical conduit for the size of bed that you are covering and with the issue of wanting to be able to open it. And be sure to use UV protected greenhouse film, unless you want to re-do the plastic every year.
