Subversion has the ability to output a log file in XML format. I think it would be pretty straightforward to implement an application in Ruby (mabe with use of Amrita), that creates some nice looking statistic about the repository.

On a side note, I have a personal subversion repository that contains everything I have accomplished during my study of Software Engineering in Hagenberg. This dates back to somewhere in 2000, and so far I am at revision 3628, and the repository uses about 500MB. It is a bit strange that 5 years worth of work can fit on a single CD 8-)