I would be interested in seeing an alternate presentation of the existing build
time trend graph. The alternative graph would have two differences:

1.) I would like to see a historical 30-day presentation, even if the job has
explicitly been marked to keep only smaller number of builds or shorter days
worth of builds.
2.) The X-axis would be time-normalized. That is, if a job has not be triggered
for 5 days, I would see that time gap show up on the graph.

I think the current graph gets its data from the 'builds' directory of the job
workspace, so to accomplish number the above, there would have to be an
additional persistence mechanism to hold the build number, timestamp and build
duration.

It would also be valuable to have a direct link to the graph (same as the
existing graph). Perhaps something like:
http://hudson-host:8080/job/my-job/buildTimeGraph30Day