1979 carver camper top

Call a marine canvas guy near you (often the same people as your nearest sail loft) and have one made. These things only last a few years so for a boat that vintage, I doubt you'll find one around that somebody isn't using, and I seriously doubt anyone is "manufacturing" them. You might find the hoop frames somewhere, that would be a pretty oblique find, but if they were the right basic configuration but for a different size boat, you could probably modify them and save yourself a few bucks on having them made, probably not much though. When you have them made, use the higher quality, preferably 316, Stainless tube and fittings rather than aluminium tubes and chromed pot metal fittings and save yourself a bunch of headaches in the future.

Get Sunbrella, the heavy Eisenglass and get screens as well, screens make a huge difference in enjoyability up there. If you have the frames already, it's a no brainer. I doubt you'll find a top end one especially for a boat like that because they will be a selling point. Have a nice one made, some storage pockets even and a wire chase to a couple of lights. Treat it with exterior grade Scotchguard at the beginning and end of every season on the canvas, and use a good UV filter cleaner/polish on the "glass" frequently and you'll enjoy it for 7 years, especially if it winters indoors or at least under cover.