Did they say anything about the price for the 138mm HR?
No haven't seen it yet, seems also this then comes direct from Cambo, but stand to be corrected by the dealers who have more info on this. Certainly going to be not cheap ...
Another point to consider - the lens is extremely heavy meaning the XT will be rather front heavy with it. This means in the field a gitzo systematic 4 or 5 becomes almost a must if you want to be on the safe side. Add to that the compendium and you really need to be careful. When I handled the Pano and 138 I was super careful as I realized how heavy it all becomes once you mount this beast of a lens.
I also think the Alpa version uses their longest proprietary large spacer in the back (meaning the setup is modular) so potentially you could maybe use tilt if you use smaller tilt enabled spacers instead of the one big one - but not sure, maybe even concatenate two tilt spacers to have tilt and swing at the same time (they are symmetric, you can combine two in different orientations) which would make the Alpa version more versatile by a large margin as you:
a) can use the tremendous IC, eg. with Max, Pano
b) can integrate tilt / swing (TBD)
Just seems like using a Bazooka to shoot pigeons when mounting a 138 HR onto an XT especially as there is no real benefit of vignetting and color cast control as the image is very even up to the edges with no colour cast to be seen.
Another benefit I see with the Alpa version is for macro / repro purposes. You can add multiple modular spacers to it to go to macro magnification when for example digitizing negatives and when using the bellows from Novoflex and the Alpa IQ back adapter. If you take the automated Novoflex macro thing you can probably also focus stack with the 138mm in macro scenarios.
I think the pure macro performance will be not as good as with the 105 which is purpose made for high magnification and has a floating lens design you can adjust, but close. The 105 does not have a shutter so this is then a trade-off. The fact that you have an X-shutter now would allow you to use flash and digitize at say 1/250 to 1/1000 meaning vibration and un-perfect repro setups are not an issue as long as you have enough flash power to go around (not swapping the LED light source below for a flash soft box, but for example to digitize reflective items such as book pages or art from a bit more high up).
The 138mm is really terrific and when shooting with it I felt the colours were more contrasty and saturated then with the 90 or 70 HR - it reminded me of the Leica APO lenses or if you add a polarizing filter to a lens - basically really high quality lens elements in there to achieve that level of micro contrast and colour pop.