rPath used by CERN
http://www.rpath.com/corp/2008-press-release-archive/rpath-at-cern.html
CERN turned to virtual appliances to facilitate the analysis of data created by the Large Hadron Collider (LHC) experiments. The complete software environment needed by the LHC applications is assembled by rBuilder and distributed to run as a virtual machine on physicists’ desktops. Virtual appliances provide a consistent application environment for the LHC applications while, at the same time, allowing scientists to use their desktops for analysis, regardless of operating system.