Glad you enjoyed the article Magga! I personally think the hardiest of all clematis are the
viticella hybrids. 'Venosa Violacea' is a very popular one that should be in every garden.
They do well in both cool and warm climates. The flowers aren't as large as some of the others, but they make up for it with a large number of flowers blooming over a long period of time. They come in a nice assortment of colors and flower shapes, and they aren't subject to clematis wilt! A great reason to grow them anywhere. It would also be helpful in your climate to mulch them well in the fall.
I hope you're able to find some so you can give them a try!