None of these are particularly uncommon clematis selections and should be available through most of the specialty mail order sources. I have no idea how one now accesses the forum archives since GW was overtaken by Houzz so I googled and found the great thread we had that listed a bunch of great mail order clematis nurseries. I can personally attest to Brushwood, Silver Star and Joy Creek. This thread was a few years ago so may be slightly out of date but most are still providing great clems by mail.

btw, none of those are wild clematis and the only one that is a species is Venosa Violacea (viticella). All the rest are late blooming hybrids in pruning group 3.

None of the ones you mentioned are species or wild clematis - all are hybrids, but they aren't the type 2 prune early, large-flowered clematis. All of them are type 3 with summer blooms, which are my favorites.

My favorite clematis nursery is Brushwood. They have a wide range including true species and hybrids in all three prune type. I also have ordered from Hummingbird Farm, Silver Star Vinery, and Joy Creek Nursery and been quite pleased with the plants from all but Joy Creek, and that's only because the order hasn't arrived yet so I can't judge on Joy Creek at this point. Each nursery has different selections, so if there's a particular one you are looking for it pays to check them all. All of them have a good variety of ones in same groups as the ones you've listed above.

When I ordered the ones I mentioned I was told they were all species and not hybrids. Fooled me. But I must say they bloomed beautifully for a long time and did not have wilt troubles. Thank you for the link to nursery websites, that will be helpful. I live in a tiny town of 1,500 and we can't buy plants here. I did drive 27 miles last week and found a Venosa Violecea and a Ville de Lyon, two favorites. They were at W-M. There is a nursery in Blair, Nebraska I will visit soon. Got Becky Daisies there last year and they performed well for me. I love the long stems and that they don't flop. This year will be a real challenge, new soil. Did take a sample of front and back planting beds to the extension office for soil tests. We'll see.