Out here in the real world, you can just buy it.
The HBO Shop is offering a full-sized (yes) replica of the Iron Throne for sale. You can own your very own for a mere $30,000. Plus shipping and handling:
I don't who keeps records of these things, but this may well be the largest and most expensive item of merchandising ever offered for a TV show. Unless STAR TREK sold a full-sized flyable ENTERPRISE when I wasn't looking.
Hey, maybe if they sell enough of these, they will do the Painted Table next!