Thanks to dkl, bmo now has an extension which shows a failure data for intermittent-orange bugs. You’ll have to enable the extension by going to the Preferences page and changing “When viewing a bug, show its corresponding Orange Factor page” to “On”. Then the next time you are viewing a bug about an intermittent orange, e.g. the current top orange, bug 789003, at the bottom right of the metadata you should see a sparkline and a count of the failures over the last week, plus a link to its OrangeFactor page. Note that the sparkline corresponds to the failure count, not to the Orange Factor (ratio of failures to test runs). If you think the latter would be more useful, let me or dkl know—it’s an easy change.
Bugs can be filed under bugzilla.mozilla.org | Extensions: OrangeFactor.