So all of these could give (principally, at least, given flawless lenses, sensors, etc) geometrically equal results, given appropriate stitching (and perhaps constraints on scene distance?)
A) Some large format sensor/lense
B) A smaller format sensor/lense tilt/shifted appropriately
C) A smaller format sensor/lense rotated "inappropriately" about the sensor centre point
Did anyone do the comparision and post example pictures? =)
I started this thread, and I now have a bit more experience with stitching Nikon D700 images (in a 3x3 grid) to emulate a single large format film capture.
Regarding geometry, the only difference is that the stitched image exhibits zero lens distortion (barrel/pincushion). Geometrically, it is perfect. (A 5"x4" film capture, or a single image from a medium format digital back, will always exhibit a certain amount of lens distortion.)
Likewise, the stitched image exhibits no vignetting and no corner softness.
In theory this is all good news, but in practice stitched images can look rather clinical.
I've recently been experimenting with adding a little barrel distortion, vignetting and grain to the final stitched image; knocking it back a little, to make it look more photographic.