duct tape WILL NOT HOLD. Unfortunately, as part of my research into this, I've spoken to multiple RV service people. Sorry, but these windows weigh several hundred pounds each. And considering what's at stake (if one "blows out", it might "blow in" again, right into you), I choose not to scrimp with safety. Can't "redneck repair" it this time.
ETA: I didn't get the new one based on its appearance. I got it because it most closely matched the physical dimensions of the original unit. The next-closest match was a white "Deco-style" one.