Even though this isn't quite on the topic of Bay Area rent, room and apartment sharing is pretty prevalent in Beijing as well, with similarily ballooning rent prices. Whilst I was living there, I shared an apartment with 3 other people, the landlord and 2 other chinese guys which were sharing their room. In fact, most of the younger foreigners I happend to hang around with shared apartments, and I wouldn't be suprised at some of them sharing rooms either. The only guy under 25 where I'm certain that he had his own flat to live in had a mother who used to work in real estate. Proably the most cramped situation that was described to me by an expat involved a girl that i met in one of the cities posher nightclubs who came to Beijing to find a modeling job, who was sharing an apartment with 5 other girls. Presumably, they did share rooms. And this is foreigners that came to Beijing despite of that. I cannot imagine how cramped some of the BeiPiao (Chinese migrants coming to Beijing) are willing to live just in order to stay in the city.

So if you're young, unmarried and you're not incredibly fussy about living together with other people, I think you should absolutely go for it. Having to share a room isn't some kind of ungodly indignity, especially if you get along with your roommates.