The PVC is more expensive than normal wood so you may be looking at the right stuff. The 44 X 20 X 22 one he says was under $50. I'm not sure if that was including the glass/plastic or not. Thin glass is cheap thou. I'll be heading to a hardware store tomorrow to play with a piece and see how durable it really is.
We have two of the big box hardware stores here and one of them will cut the glass they sale the other will not. So if you bring them the measurements they will cut it, now they are not exactly "good" or "trained" at this so you take your chances. That glass would still need to have the edges sanded/polished and that's a bit of work. Read up on it before you do it if you go that route, glass dust is some nasty stuff. Or you could go the route I'm planning on and that's to find a good local glass store to cut and polish the edges for me, it will cost a bit more but I think it worth the money in the end.
For a setup you plan to move something similar to that linked one might be perfect, just build the sliding glass doors so they are removable and the rest would be a wooden box. The plastic or glass panels would reduce the weight and cost a lot. Although you could do that with normal plywood and Pond Armor or the like.