Is there any evidence that the naked short selling was a real thing beyond the insistence of the CEO?

Pop over to deepcapture.com and see for yourself. (It's maintained by Overstock's CEO as a side project, but it seems to me that the endless stream of scathing accusations would have brought swaths of libel suits if the stuff had no basis in reality -- enough for them to defend themselves against a court shutting them down anyway.)

"Hasn't been sued for libel yet" isn't quite the quality of evidence I was looking for.

Think of it as a proxy… Follow the links and the references on that site, and see for yourself. The site has tons of them.

I didn't look into it further. A lot of counter suing going on.