A great story, but I'm having a hard time thinking up a terrible joke that combines a line from the Shakespeare play with "found under parking lot." I thought of, "A Ford Mustang! A Ford Mustang! My kingdom for a Ford Mustang!" It's definitely awful, but not quite clever enough. Alack.
I believe the line you're thinking of is, "A Hearse! A Hearse! My Kingdom for a Hearse!"
Since no one has gone there yet- Prince Albert was found in a can.
I'm from New York. We have plenty of skeletons under parking lots.
(Honestly, I thought it'd be more.