Why is no one building Garrys (the name has 2 r's)? I'd guess it's a combination of: (1) form loss after Chestnut cratered in the mid-1970s (the forms were probably in pretty bad shape at the time, like most of Chestnut); and (2) lack of interest in a big wood tripper when kevlar/S-glass/plastic are the material of choice for wilderness canoes.
Ken Solway acquired a Garry mold at one point but, try as I might, I was never able to get him to build me one. His business, it seemed, was mostly recreational Chestnuts. I don't know that he ever built a Garry.
No great wonder. It is a pretty specialized boat. Like all Prospector models, the Garry was designed for large loads in the woods. It is very deep (close to 15"). It's also very heavy. Even with #10 canvas (mine was originally supplied with #6), it's north of 85 lb after a week of paddling. That's a lot of canoe if you don't really need it. I suspect few people today want a boat that is poorly suited to general recreational paddling (unloaded, it's a sail in quarter and beam winds), and big/heavy to boot. I like mine fine for trips but, given a choice, I'll take a smaller or sleeker boat out for the afternoon spin.
Here's my answer to the original post: find a good Prospector from the 1950s or early 1960s, refurbish it and use with good cheer. Failing that, convince Rollin Thurlow to take the lines off a good model and expand his catalog into the world of Chestnut.
BTW, similar to Sherman Tanks, my Chestnut was pretty cheap. I bought it in 1965 for $250.