Another vine that is (bluish at least) is Passionflower "Incense"- beautiful flowers, fruit, hardy. But it can come up like crazy from the ground and would have to be confined. A big container would do where you are-I bet it would overwinter well in one. And the smell! heavenly. I was able to overwinter them fine in Ohio with a heavy mulch.
I saw a beautiful blue clematis on sale a few days ago..just such a clear sky blue. Not sure how well they do down south though.
Are there any blue hardy verbena groundcovers for down there? Blue is such a hard to get color anyway, and to find something that could take the harsh heat and conditions of the summer in the south....
* My Invicta Gooseberry has set so much fruit that I had to prop it up with six bamboo poles. And this is the largest fruited one there is. I hope the dumb thing does not break or something.