For my master’s degree I modified CVS to allow a repository to be distributed across multiple hierarchically organized servers. The motivation for this project was to make it easier for one engineering team to maintain a modified copy of another team’s project than is possible with CVS import (which often has high administrative cost).
The project was a success in the sense that I produced a working proof-of-concept implementation, and a failure in that after spending a year working on the guts of CVS I decided it was much too painful and moved on to other projects after graduating.
Download the thesis and the slides from my degree presentation.