The same way there are permalinks to "lastStableBuild" or "lastSuccessfulBuild" it should be possible to have a "lastPromoted" with a specific level either given as parameter (lastPromoted=1) or part of the link (lastPromotedQAbuild).
Of course the names depend on how they are defined in the configuration, for example I currently have the following 3:
- QA tested
- QA approved
- GA released