Airbnb is frequenty cited as a counterpoint to all the bubble talk because they have a real business model and are making money. Same goes for all the other highly valued YC companies(Dropbox,OMGPOP,Heroku,etc).
We originally wanted to work in our apartment forever. We figured we could fit 100 people in 5 apartment units in our building. Assuming we would need to scale beyond that, Joe and I talked about renting every home on the street. Imagine product in one house, marketing in another... Wasn't really feasible though.
Zoning as only one issue. You most definitely can't run a business in a residential apartment, condo, coop or neighborhood. In some neighborhoods you might slide by depending on the makeup and the neighbors.
That sounds amazing an scary at the same time. Wonder if you could try it out for a new product team, that's fairly isolated from rest of the company. A startup within AirBnb?