Community question here with some traction: https://answers.atlassian.com/questions/50451/how-to-modify-project-summary-to-add-custom-gadgets

I would at least like to be able to remove certain metrics. For instance, I don't use Components for one of my projects. Now on the Issues overview that metric is just taking up space, and above the "Unresolved: By Issue Type" metric to boot, which is rather important.