While it never happened, and the contents were likely set to be included in Gary's 2e rewrite of AD&D, it seems that an Unearthed Arcana II was planned and at least mentioned in internal documents and things provided to distributors, and possibly retailers. I say this based on a snippet of a discussion in a GM Publications modazine (module / magazine) where they mention having seen the TSR Catalog for this year, provided by Virgin, with this item listed as "forthcoming" (as was the Immortals box set, among others.) My curiosity simply wonders, since some of the stuff to supposedly have been included are a few classes like savant and mountebank, whether there was more to the listing -- a sample, maybe? A cover concept? Anything more than vagueness...

And on the subject, I wonder how much of the foreword to "Unearthed Arcania" should be considered OAD&D canon / errata.

I do apologize if this is a repeat -- there are just too many pages of pages of pages.

Here's a scan of the comp cover used in the catalog.
The "moire" pattern is an artifact from scanning.

It's called "the Lantern Maker" by Jeff Easley and it's from Amazing Science Fiction Stories in July 1984. It also appeared in the Art Of Dungeons and Dragons book from 1985.