Scott is right in that you probably won't ever need to replace the canopy or rear window.
When I bought this one, the rear windows was the original polycarbonate. It was badly crazed and cracked from contact with MOGAS, and looked like ****. It wasn't getting any better with time. During the CI the year before last, we pulled the rear window and replaced it with the new acrylic window, using Sika instead of screws. Looks great, wasn't a big challenge to do. You just have to figure out how to hold the window in place from inside while the adhesive cures. An air mattress and exercise ball did the trick. We're REALLY happy with how well it turned out.
The bottom right corner of the canopy was also broken from a wind incident before I bought it. A good sized chunk of acrylic was broken out, and there were a couple of cracks. Nothing that couldn't be fixed if you don't mind the repairs showing, but then we discovered that the weld was broken, too. That was the tipping point. I put in a temporary fix -- structurally OK, but not too pretty. I have a new frame and canopy here. I don't know that the Sikaflex will be any more or less difficult than the screws and rivets... more taping and all, but zero drilling. Everything sits perfectly in place, so we won't need to go through some of the clamping gyrations I've seen others with RV-7s and 8s. I am thinking about maybe using fiberglass instead of aluminum for the side skirts... haven't decided yet.
Like I said, I'll post the process and results here once we get around to finishing it. I will say this: I was a little leery of the Sikaflex, but after seeing it in its final state -- no way that canopy will ever work loose. It's some pretty tough stuff.