I agree, this could be an excellent solution: phase detection for rough focus and contrast detection for fine focus. Speed + accuracy.
Oh, then that could be already done with a semitransparent mirror as in the A33/A55?
I was writing about phase detectors in the sensor, that may offer both speed and accuracy (as focus is measured exactly where the image is formed) - no need for contrast AF anymore as far as i can understand.
http://www.dpreview.com/news/1008/10080505fujifilmpd.asp
