Is this the one? The sign was on a parcel on Flamingo road near Koval, I think. (In between the rear of Bally's and before you get to Quality Inn/Key Largo Casino.

It just sat there for a number of years. Never any real attempt to build a casino, notwithstanding what the sign said. I believe the property has sold and some time-share suites are being built there now.

If I've got it wrong, I'm sure one of the LV locals will set the record straight.