Moog Music annouced today that the Moog Etherwave Pro theremin is no longer available from Moog Music directly. Instead, you'll need to search for one on eBay or other sales forums. The new Limited Edition Etherwave Pro features a natural wood back instead of the solid black backing of the original model.
I'm unclear at this time whether or not all the dealers will carry the Limited edition or not (and it appears some of the dealers they list don't even have the original version anymore), but as soon as I know more, I'll update this post.