Ha, Olympus Big Announcement that will be made next week nothing has to do with the MFT system. There will be an updated 75-300mm II lens but that's all. That what Olympus defines as big news is "just" the new XZ-10 compact camera. And Sony too will announce the NEX-3N only after the CP+ show which takes place in Yokohama from January 31. And what about Panasonic? New GF and G successors are also coming in a few weeks only.
In summary this is what we can expect to be announced in March-April:
Olympus: new semi pro PEN model
Panasonic: New GF and G models
Sony: new NEX-3n
Samsung: new NX300 and maybe a new NX Full Frame surprise
Canon: new EOS-M with integrated viewfinder
Ricoh-Pentax-Nikon-Fuji: No info about new camera releases yet...
Or you may heard about some mroe cameras? Drop me a message at email@example.com if you have some secret bits to share :) Thanks!