Hi Will,
I rented a "golden throne chair" that looks much like the one in your reference photo.  It was professionally built and very sturdy.  It was very ornately formed out of solid resin. 

I used it as Gaston's chair in a youth production of "Disney's Beauty and the Beast" by adding temporary horns to the top with wire.   Here is a photo.  (You should be able to click on the photo to make it larger). Throne DBATB.

Here is a better picture of the chair, (disregard the kid in the photo): DBATB Throne.

If you wish to rent this chair, it's at a clown & magic supply store in Greensboro, North Carolina.  Maybe they can ship it out of state, I don't know, or maybe you could make the 5 hour drive up here.  But anyway,  their website is:  A rental place.

Hey, if you can get by with a more rustic and less ornate throne, then I have one in my prop room that might work for you.  I have two matching thrones actually.  They are made of solid hardwood - in sort of a Shaker style.  They were donated to us many years ago from an old Masonic temple.  I've used these wooden thrones in about a dozen plays...from Shakespeare to Cinderella.  Here's a photo from the "Be Our Guest" dinner scene in that same middle school production of "DBATB": Rustic Throne Chair.

Good luck with your project.  -Dana

 Will, sounds like we are in the same boat, I am building 2 thrones for Beauty and the Beast, one from scratch and Im revamping another. the following pics are the one that is getting the makeover, the first set is what it looked like a few years back for I Hate Hamlet,( plus the whole set)