I had never seen them until I bought one a while back-Inxs gave me the same info. I don't think there's many of them around, I've seen and owned quite a few xs, and mine are the first ones I had seen. Really nice rims, and a little different. I'm gonna re-lace mine and use them on a current project-maybe scotchbrited, maybe polished.
That would be a good buy-a Sun rim or similar is $125, and I doublt you could get it in a 16 inch.
John