Elon Musk just listed 5 more mansions for sale after pledging to 'own no house.' Take a look at the $100 million real estate portfolio he'll have to offload to make that happen.

· Elon Musk vowed to sell "almost all physical possessions" including his homes in a tweet May 1.
· Five of Musk's mansions appeared on Zillow as "for sale by owner" Wednesday. The Tesla CEO had already listed two Bel Air mansions on May 3.
· Musk owns at least seven houses worth a combined $100 million, including six...