The Japanese website Egami (Click here) found a new Olympus patent describing different variations of a new 150mm f/2.8 macro lens. There are actually two different versions. One shorter lens for the m43 system and a longer lens for the Four Thirds system. Both are described as high quality optics. The only similar lens currently on market is the Sigma 150mm lens (here at Amazon).
One more thing: I am currently sorting out your lens suggestions for the m43 system and will soon publish the poll.