I don't shoot much formal landscapes per se - more travel photography than anything, and I sell my work through both an art gallery and an interior design store. Examples of my work are on my website at
Peter Mendelson Photography. My most common size print is 40" x 60" so resolution is important to me.
I will be using the 645z whenever practicable, but I will be using a smaller system a lot of the time too when I don't want to or can't lug around the 645z and lenses (the 28-45mm lens is an absolute beast). I got the Leica Q when I wanted a one camera / one lens solution for carrying around. I loved a lot of things about it, but the smaller resolution files were a bit of an issue for me. Also, I use the A7RII and 25mm Batis a lot, and it's not much bigger than the Q so they were a bit redundant for me. I recently tried out the Sony 24-70GM, which would have been great for my trip to Costa Rica, but the lens was soft on the right edge (possible decentering?), and I returned it. It also wasn't much fun to shoot with for some reason - over time I have grown to like shooting with primes and the challenges they present.
I have an upcoming trip to the Amalfi Coast with my wife this summer, and I'd love to bring the 645z, although it is going to be a bit uncomfortable carrying it around everywhere. I think I am going back to backpacks from shoulder bags