Silver Strikes up for sale.

I dont know about "rare" but perhaps more valuable to collectors. If you look on Ebay at other strikes from closed casinos they seem to go at a premium. Westward Ho, Stardust, and even Sahara now seem to be selling for a few bucks more.

I snagged the El Cortez strike. Lost the other two.

absolutely, closed casino memorabilia is more collectible than something from a casino still operating.

One day my set of 12 beer mugs from NYNY will be worth something... ummm.... 11 beer mugs.... one was used as a pencil/pen holder.

When my friend moved to Vegas, his job fell thru and he found himself unemployed and with a lot of time on his hands. He started collecting free stuff from casinos and selling them on the internet. A very popular package was ten books of casino themed match books with a starting bid of .99 cents. Sometimes they'd hit $5. Decks of cards bought a buck or two, even coin cups were solid sellers at 3 or 4 for $5. It really helped him out while job hunting.
Somebody, someplace wants that Hooters visor you got for signing up at the players club, and the internet is a great place for them to find yours.