In the Ultra-Large-Scale Systems (ULS) seminar we are reading the Carnegie Mellon report which makes a case for ULS systems as a new and legitimate area of research. This seems to be somewhat of a hot topic right now, including a special discussion session at OOPSLA last year and a workshop earlier this year. The fundamental problem with this research is that it involves considering things that most systems computer scientists do not consider (such as the social and economic aspects).
One particularly prevalent consideration is how the open-source movement fits into the models (See the Cathedral and the Bazaar). The semi-altruistic behavior of open-source software development has proven its staying power. However, these ULS systems will be developed by and for the government (at least initially), and will therefore not be open-source in the conventional sense. However, open-source-development-like behavior may be exhibited by competing government contractors.
Also the longevity of ULS systems may necessitate open-source models in order to remain relevant. These systems will take a long time to build, and will take even longer to be replaced. "Many eyes makes all bugs shallow," so open source may be the way to go. However, how does one put automatic driving, a hospital, or the military in the hands of open-source and feel good about it?