Autofocus - Depth Information

Hi,

a quite specific question about autofocus, more exactly the depth
information (SubjectDistance tag in the EXIF info - for Canon Cameras).

Which are the cameras with the highest number of focus points possible?
Is there any camera where the SubjectDistance information for a
specific focus point can be read out via a PC connection without making
an exposure, just in the phasis where focus measurements are made by
lightly pressing the shutter release knob.

I would like to use the camera to roughly approximate / sample the
depth information of the visible field through the viewfinder.

I would appreciate any thoughts / ideas about this.

Thanks,

Andrei.