I'm jumping in a bit late on this thread as I'm in the middle of moving from Malaysia to Switzerland.
Tim, I have some reservations about your conclusions about your torture test.
The 35XL, for all its vaunted reputation, simply does not have the resolving power to match the IQ180. I had one, and have tested several others and my view is that it does not come close to the res my 23HR or 40HR deliver. Good, but not great is how I would describe it. Hence, your test is in my view not producing the best file the IQ180 is capable of.
However, taking on board your other considerations, I think your general thoughts on the right gear for you are fair enough. For me, I have decided that 35mm platform is useless, and am selling all my gear and will shoot almost exclusively IQ180/Alpa STC/ Rodenstock glass. I have a DF system, but it only gets used occasionally, usually when I need longer lenses for people shots.
BTW, I can assure you that Phase does not have any instructions to its dealers re: pricing on used gear. That's a decision individual dealers make. Of course as a commercial decision, it doesn't make sense to devalue the market. Best you sell privately. It takes a little effort, but I have sold my P25, P65+ and Aptus 12 this way.
Good luck with the journey!
Cheers,