Mavic Open Sport, a lower profile, lower priced hoop than the Open Pros. MA3 was the old model that Open Sports replace. MA3s were favored years ago, they were sturdy. I can't see anything being better than Open Pros practically. So unless you want to search quite a bit, I don't see many choices in 36 hole selection which is contra-retro anyway for the most part but 32 hole rims are easily found NOS etc.
Harris sells them. I've used Excel Sports in Col. too.