I have already reported pretty much everything you need to know for the new Olympus E-M1X camera that will be officially announced tonight (around midnight EST):
To get an idea of the E-M1X size, here are a few comparisons between the Olympus E-M1X ($3,000), Nikon D5 ($6,497) and Canon 1D X Mark II ($5,499):
Olympus E-M1X vs. Nikon D5
Olympus E-M1X vs Canon 1D X Mark II
Source: Apotelyt, via FujiAddict