I'm in Boston at Drupalcon 2008, in a discussion of working together and not reinventing the wheel, where the participants are from competing development shops.
They're looking for ways they can work together, to avoid duplication of effort, and reduce their overall costs.
I find it amusing (and sad) that the company I work for (on the corporate level) has the same problem, but doesn't seem to be working toward solving it.
At last count, we had at least four, possibly five versions of the same proprietary authentication module. Within one (admittedly large and geographically scattered) company. All interfacing to the same systems.