Thanks for all the great ideas.
My brother ended up getting me a rangoon creeper, which he knew I had been lusting after for a couple of years. It's supposed to be zone 10 but I know a couple of people north of me have them and have good luck with them. It also might be too heavy for the trellis, but the research I did says it takes well to clipping to keep it under control. We shall see. In any case, I LOVE this vine! :)
Thanks again everyone.