Rails Stats is a simplified graphical version of the Rake ‘stats’
task. It generates a graph showing your lines of code versus lines of
test code, and two other graphs showing the composition of your
project and tests. The plugin requires Gruff Graphs.
http://shanesbrain.net/articles/2006/07/18/rails-stats-plugin-or-show-me-those-pretty-graphs
If not useful, I hope someone finds it pretty 
Shane V.