Casino dice - where to look after the obvious places?

I have a collection of casino dice from Vegas casinos. However, after going to the obvious places:
* The casinos' gift/sundries shops
* Bonanza Gift Shop
* Gamblers General Store (where the collection consists of pretty much the same casinos as Bonanza, plus a large pit of dice not separated into pairs, and most, if not all, of which appear to be from non-Vegas casinos)
there are still a number of places with craps tables where I can't find them:
* Casino Royale
* Circa
* Circus Circus
* Cosmopolitan
* Fontainebleau
* M
* Park MGM
* The Pass (not to be confused with Railroad Pass, where I do have a pair)
* Resorts World
* Sahara
* Silver Nugget
* Virgin
* Westgate
Any suggestions?
I know that Viva Vegas stores used to carry dice, but I haven't seen any in any of those in years.

Ebay has a lot of casino stuff.
McManus Auctions is Vegas's biggest auction house and now has a store as well. They don't always have gambling memorabilia, but when they do, it can be interesting.