A quick search and I found this. I have no experience with this nursery...

Here is a link that might be useful: buddleia alternifolia

Thank you for that. Another member referred me to ForestFarm, with whom I've dealt on several occasions. I don't know why I didn't think to check with them first. But they do have some available now. Yay!
It's nice to have a backup too, though. Thanks for your response!

Ha! You had me running out to check on mine. I live in California and bought it as a 1 gal. at a local nursery last year. I'd never seen one offered here before, and like to try out different plants. It is tucked away in the corner of the garden kissing a species fuchsia, whose growth habit and leaves are very similar except for a bit more leaf width. I'd completely forgotten to check on how it was doing this spring! I'm was happy to see it is still alive and growing. :)