Good point on the Alpa FPS, I did over look it and as you point out a great solution, as one system/shutter works on multiple lenses. I guess there is no leaf shutter option on the FPS? So flash sync advantage for faster shutter speeds would go to the XT.
What has fascinated me is the way the various users justify the design, and gloss past the glaring oversights, 12mm of shift in one direction and no tilt.
I have seen article after article stating that the max shift of the 32mm Rodenstock by design is 12mm, and the 40mm since it's not available doesn't count. I have the 32mm and know it can make easily and at time 20mm. Where the XT design really falls off is on the longer glass, like the Rodenstock 90mm which can make 25mm of shift (HR-SW), or the Schneider 60mm, or the Rodenstock 70mm and 50mm, both of which will easily shift past 12mm. If the goal is pano creation with no parallax, then the more shifting of the back, the better.
Tilt, is the larger oversight as I use it with all my lenses. Even the 120mm Schneider. and for sure the 90mm Rodenstock.
Yes you can add the Cambo T/S adapter, to a XT mount, but then you have a cable, an lose one of the main selling points of the XT, all integrated, no cables.
Paul