Wouldn't the point of a pellicle mirror be to show a TTL view through the viewfinder? Why would they go through the trouble just for the AF? As mentioned earlier, there will be a delay in the display to the EVF, which sort of defeats the point of a high speed camera; you can't shoot the catch that you can't see. And - something I just thought of - you'd still have blackout while the shutter is moving across the sensor to make the exposure, hence defeating the pellicle mirror again.
Modern EVF tech can still give a faster visual readout than your brain can process to react, so there's really little to know real-world delay for good EVFs nowadays. Most of what's been put in still cameras up to this point (with the exception of the Panasonic G1/10/2/H2) has been a bit behind the capabilities of the technology.