I would like to add dev-python/medusa as a test dependency to dev-util/bzr (a bunch of tests are skipped if it is not available). To do that it needs an amd64 keyword. Medusa itself is a library so a bit hard to test, but you could merge an existing bzr ebuild with FEATURES=test (it will use medusa to run the ftp tests if it is available, and those tests should pass).
Keyworded 0.5.4 ~amd64