Aegis is a transaction-based software configuration management system. It provides a framework within which a team of developers may work on many changes to a program independently and Aegis coordinates integrating these changes back into the master source of the program, with as little disruption as possible.
I found this quite interesting project in the current issue of the german Linux Magazin.
It seems that it can use different RCS backend systems like CVS for example. An integration with Subversion would be the Perfect Solution (TM).
Let's see what the future's bringing us ...