King Kong is one of the most rare pinball machines out there. Like Kingpin, it was never put into full production, so there are very few machines that were ever produced. Essentially, Data East was never able to secure the rights for full scale production, so the game had to be scrapped even after some prototypes had already been fully assembled.
Right now there’s a King Kong up for sale on eBay. Bidding, as of the time this post was written, is up to $20,000 and rising. There are several pics of the machine, which looks to be in mint condition, available on the auction page.
If you want to bid, or if you just want to follow the progress of the auction, check it out here: http://www.ebay.com/itm/130971892352