I'm pretty good at finding things I want to find, and I found zero sleek wands. To be fair, I didn't have the character that long, and I never reached the level where detect artifact would have fired on barrier. But I did get detect artifact, and I did check almost every location on the "list of possible wand locations" I had cooked up prior to rolling the character. Some of those locations I knew were sleek spots because I saw mages use them while I was playing other characters.

In retrospect, though, I think most of the spots I know are legit because I saw other people use them are actually sleek blacks. So if I'd stuck it out then I might have had a good shot at finding my sleek black. Just had no luck with amber/sienna.