A startup in San Francisco that rents out bunkbed-style pods large enough to fit a twin mattress is overwhelmed with demand for its $700-a-month living quarters. The company, Brownstone Shared Housing, operates out of a former bank in downtown San Francisco. The pods are 3.5ft-by-4ft-by-6.5ft with a privacy curtain; rent includes internet, utilities, and access to shared bathrooms and a kitchen.