According to multiple top sources we will have at least three announcements between early April and early May:
1) First announcement form Panasonic in early April
2) Second announcement from Panasonic in late April-early May
3) Another announcement from Olympus in late April-early May
Panasonic is likely going to announce a new G and a new GF model. I am still not sure about a possible new GX model although the recent massive price drops suggest that a new camera may be on the horizon. The 42,5mm f/1.2 and the 150mm f/2.8 lens are NOT going to hit the marked for the next 6-8 months.
Olympus is likely to announce the new E-P5 (with no built-in EVF), a new fast f/2.8 zoom, a Black 17mm f/1.8 lens and a new external viewfinder with 2,44 million dots.
What else can we expect? Maybe a new Blackmagic MFT camera with full electronic support, maybe one of the preannounced Schneider lens. Zeiss is NOT going to release a MFT version of their three new primes for the NEX and Fuji X system.
Rumors classification explained (FT= FourThirds):
FT1=1-20% chance the rumor is correct
FT2=21-40% chance the rumor is correct
FT3=41-60% chance the rumor is correct
FT4=61-80% chance the rumor is correct
FT5=81-99% chance the rumor is correct