Robert..have you been introduced to the search function over at COTW aka Clematis on the Web?..You just click on search and then click on Texensis under group and it will show you all

Here is a link that might be useful: Texensis

The only one that comes to mind right off the bat that is not on your list and I have ever heard of is Lady Bird Johnson but I haven't seen her available any time within the last couple of years. Jeanne steered you to the right resource though realize that there will likely be many varieties there that are not available commercially here in the US, if anywhere at all.

Just looked and Lady Bird Johnson is supposed to be available from Chalk Hill this fall.

Here is a link that might be useful: Lady Bird Johnson at Chalk Hill

Clematis texensis 'Peveril Profusion' looks gorgeous.
I don't suppose it is available in North America as yet.

http://www.prideofplaceplants.com/vines/clematis_pev_profusion.html

Clematis texensis 'Rapture'

http://www.prideofplaceplants.com/vines/clematis_rapture.html

Clematis texensis 'Ruby Wedding'

http://www.prideofplaceplants.com/vines/clematis_ruby_wedding.html

Waaaaahhhhhhhh I want all of them.

helpmefind.com might also be useful, they have a subsection just on clematis and you can search for texensis. They also have places the varieties can be bought at, if you look at the tabs at the top. Took me a while to find the tabs--ooh the photos too!

Well if I knew that they were as prolific as Duchess of Albany I probably would want them as well Helen. But since my Princess Diana and Gravetye Beauty are such wimps as far as flower production and susceptibility to mildew, I will stay away from them.