I need your recommendations for continuous build products for a large (1-2MLOC) software development project. Characteristics:

• ClearCase revision control
• Approx 80% C++; 15% Java; 5% script or low-level
• Compiles for Green Hills Integrity OS, but also some windows and JVM chunks
• Mostly an embedded system; also includes some UI pieces and some development support (simulation tools, config tools, etc...)
• Each notional "version" of the deliverable includes deployment images for a number of boards, UI machines, etc... (~10 separate images; 5 distinct operating systems)
• Need to maintain/track many simultaneous versions which, notably, are built for a variety of different board support packages
• Build cycle time is a major issue on the project, need support for whatever features help address this (mostly need to manage a large farm of build machines, I guess..)
• Operates in a secure environment (this is a gov't program) (Edited to add: This is a classified program; outsourcing the build infrastructure is a non-starter.)

Interested in any best practices or peripheral guidance you might offer. The build automation issues is one of several overlapping best practices that appear to be missing on the program, but try to keep your answers focused on build infrastructure piece and observations directly related.

Cost is not an object. Scalability and ease of retrofitting onto an existing infrastructure are key.

JA