I don't think we ever canned any green tomatoes, but every time we got to Ardmore, OK, we have to stop for lunch at Louie's Catfish Corner. It's one of those old buildings that you wouldn't consider stopping at if you were just passing through town, but they have an excellent catfish lunch that includes "Green tomato relish"; pretty big chunks of green tomatoes, slightly sweet. Louie's specializes in catfish and Mexican dishes. We've never tried anything but the catfish, although the Mexican food we've seen delivered to other tables certainly looks good. And I don't know of any place with better and faster service. My wife doesn't care for the green tomato relish, but I like it.
My wife makes a sweet relish with yellow summer squash that's great. We have Big Red Smokey dogs with the relish, mustard, chopped onion, and topped with Sauerkraut. The topping is so deep you have to eat them over a plate to keep recouping what falls off.