I believe only New Frontier, Harrahs, New York NY, and Sahara use the $2.50's, Jay. The others you listed have issued them, but don't play with them. If anyone knows different, I'd like to hear about it.

Other LV clubs still operating that have issued $2.50's but don't use them are:

Riviera
Horseshoe (poker only)
Lady Luck
Silver Nugget
O'Sheas (club commem)
Nevada Palace (chip show commem)
Fiesta

Doesn't hurt to ask at the cage as you might find an older one there. Lady Luck hasn't used one for years, though. They have issued three different designs.