GigaOm Pro, a paid subscription site, has an article covering the financials associated with the operation of two coworking facilities.
Since I don't want to violate their copyright, I won't go into detail here. The bottom line from their article is coworking facilities, at best, operate on thin margins.
This analysis highlights that coworking facility business models are still a work in progress. This issue could impede the broader growth and success of the coworking movement.
The good news is lots of business model experimentation is going on the in the shared workspace area - and there are lots of new entrants with new approaches. It seems likely that strong business models will emerge from these diverse efforts.
BTW, I subscribe to GigaOm Pro and find it very useful. They are also an interesting example of a disruptive business model. They are providing good research at a substantially lower price than offered by traditional analyst firms.