You should look more closely at Manhattan and SF. There is a ton of speculation, luxury highrises, and out-of-town wealthy buying second-, third- or fifth homes.
Anecdotally I see a lot of empty apartments here in SF. Not as bad as London though. I basicslly had an entire massive luxury apartment complex to myself. I would walk around the halls drinking with friends carrying a prop ax pretending we were in the shining. Good times.
