The auctions, which can be seen here and here, are offered by Collectible Investment Brokerage. They reveal concept art for a Raven Bar playset and a Temple playset based on the classic scenes from Raiders of the Lost Ark.
It isn't known exactly why the toys were never made. Considering the Indiana Jones line didn't sell well at the time and was quickly discontinued, the playsets were likely part of a future wave that never made it to production. The line only lasted two waves, from 1982 to 1983.
Check out the images from the auction (click to see a larger version):