Jack,
see my answers below:
1) Am I correct in that it only shifts and tilts while mounted conventionally, and that you have to turn the camera 90 degrees to get Rise and/or swing?
No, wrong: you don't have to turn the camera to get rise or swing!
All movements are available a such.
Concerning the tilt/swing movement: this is possible in both directions (combined tilt and swing = double Scheimpflug). The front with the lens board is rotating. Thus an initial tilt of x degrees becomes a combined movement of the sharpness plane when rotating the lens board somewhere between 0° and 90°. At the position 90° the tilt axis becomes the swing axis. So all 3 plane adjustments are possible: single sharpness plane adjustment around the H-axis, single sharpness plane adjustment around the V-axis, and double adjustment of the sharpness plane by using the rotation around the optical axis.
2) If 1 is correct, then there is no way to get rise and tilt or shift and swing at the same times?
The horizontal and vertical shift movements are 2 different and independent movements/knobs, working and moving separately of the rotation of the lens board.
3) It also appears it is swing or tilt only and no way to have both combined?
Wrong: combined tilt and swing for double adjustment of the sharpness plane is possible: see above.
4) Finally, it appears the tripod mount is not centered under with the lens when the lens is zeroed? Wouldn't it be desirable to have it so for nodal (panoramic) stitching?
See answer to the very same question here:
http://luminous-landscape.com/forum/index.php?showtopic=26265&st=60
Post N° 72:
"the 360degree plate in the tripod came in the camera, because we discussed to include this as a little detail, after i brought my tripod to sinar and explained whi i use this strange manfrotto leveller.
i shoot usually with this leveler to get a horizontal platform under the three way head, or under which head i ever use. in this way i can turn round the camera meanwhile i compose and adjust the image without that the horizontal position gets lost.
to integrate this rotary possibility in the camera mount itself means that, one time you have the camera horizintal adjusted e.g. with a three way head, you can turn it around its axe and you dont have to adjust the horizont again. this should be a very practical detail.
of course one can use this feature also for "real" stitched roundshots, but it was not my intention when i asked for this feature
i.m.o. a sliding back camera can never be a perfect roundshot camera platform and it will not be used often for this purpose, but you are right,- smetimes it will be used therefor".
Best regards,
Thierry