There has been a lot of rumors about Canon making a move into the medium format segment, it's even been suggested we'll get a development announcement for such a camera at Photokina in September of this year. Canon has recently moved into security cameras and industrial cameras to find growth in new markets, it would make sense to give an EOS branded medium format system a go.
Sony, a big manufacturer of medium format sensors for the likes of Hasselblad are rumored to be readying a medium format system of their own. It would use the 50mp sensor currently found in the upcoming Hasselblad H5D-50C.
Sensor Type: 50 Megapixels CMOS (8272 x 6200, 5.3 × 5.3 μm)
Sensor Dimensions: 32.9 x 43.8mm (sensor is physically 70% larger than a Full Frame sensor)
Image Size: RAW 3FR capture 65MB on average. TIFF 8 bit: 154MB (on the Hasselblad H5D-50c).
It's noted that Sony has no interest in competing with Hasselblad or Phase One and that their medium format camera would be something “completely different”. Perhaps a compact MF system?
Sony is being quite aggressive in trying to find new markets in still cameras, and if the system is priced affordably for medium format, they could have a winner if this true.