A little off subject, but while looking for other patents I found this which I thought was interesting.
Canon patents for 600mm f/4 and 400mm f/2.8 lenses | Photo Rumors
Both of these Canon lenses filed at the same time have "image height" of 21.64mm. There is also a 35mm F/1.4 and a 180mm F/3.5 Macro from Canon that have the 21.64mm image height.
I think the "Image Height" is misleading.
21.64mm x 2 = 43.28mm which would be 0.15mm larger than a full frame image circle needed to cover a 24x36mm sensor. I think "Image Height" is actually the radius of the image circle.
The Canon 24-70L F/2.8 II has an Image circle of 43.28mm. This seems to the Canon standard for image circle.
That would make the Pentax 70-200 F/2.8 with an "image Height" of 21mm a "near" FF lens with an image circle of 42mm or 1.13mm smaller than a TRUE 24x36mm. You need 43.13mm to cover the FF sensor.