Will Oly do a 150 f2.8 and when?

The easy answer to your question is "maybe and sometime in the future."

This is definitely an interesting time in µ4/3. If some of the rumors are true, Panasonic is soon going to release a new kit telephoto zoom. Probably less range (45-150 vs. 45-200), but hopefully a little smaller to pair with the smaller bodies and possibly play nicer with 1080p and some of the other technological advances that have come along since the first µ4/3 cameras were released. And we know the next lenses to be officially announced include Olympus' 60 mm macro and Panasonic's fast tele zoom, along with whatever else they, K-S, Sigma, Samyang, etc. may announce leading up to Photokina. Will the established members of the group continue to invest time and resources in revising established models to take better advantage of the newest features of the bodies? Or will they push in new (and hopefully exciting) directions?

For me, the Olympus collection of glass, right now, is the most exciting, but, as a new owner of a GX1 due to the great deals available over the last couple of weeks, I'll have to take into account the lack of OIS in Olympus lenses (the good news is that I was a Nikon owner for a long time, and unstabilized primes aren't new territory).

I'm okay with Panasonic and Olympus holding off on developing fast long glass until contrast focus detection can better keep up with the subjects you use those lenses for (sports, animals, birds). But I agree that something like a 200 f/4.0 would be a nice addition.