bfgminer is maintained by luke-jr and the github can be found project here. cgminer is also available. These versions have been compiled for Mac OS 10.6+ by John O'Mara, creator of MacMiner, so that they can be used without a lengthy install process. Instructions are included in the download, if you have any problems please check the forum.
These backends often trail behind the versions in MacMiner so if you need a newer version please show package contents on the latest version of MacMiner