rfaspen
[insert pithy phrase here]
Hmm, I wish an M9 could be had for your budget. I would think the A7 is going to be your best bet if you want to use your M-mount lenses to their best potential. Use Cornerfix on your wide images for now, and get the thin cover glass conversion (Kolari?) when your budget rebounds a bit. Then you'll be set. I see pre-owned A7's at your budget quite often.
I personally wouldn't consider any of the smaller format cameras. For me, I've found that I just need full frame for the familiarity of focal length behavior, DOF, and the image quality tends to be quite nice as well. I own some m4/3 gear, and I use it, but its sufficiently different than what I've used for so many decades that it affects how I feel while shooting, and ultimately how the photos turn out.
Now having said that, I wonder if you really want to take your "nice glass" and "new camera" on a trip that has such hazards to their well-being. I know, why have stuff if you don't use it. I also subscribe to that philosophy, but I also believe one should use the appropriate tool for the job at hand. That would steer me toward a ruggedized camera. Everyone needs one in their gear inventory anyway, so might as well get it now and be done with it. I heard the Olympus version lives up to its marketing hype...
I personally wouldn't consider any of the smaller format cameras. For me, I've found that I just need full frame for the familiarity of focal length behavior, DOF, and the image quality tends to be quite nice as well. I own some m4/3 gear, and I use it, but its sufficiently different than what I've used for so many decades that it affects how I feel while shooting, and ultimately how the photos turn out.
Now having said that, I wonder if you really want to take your "nice glass" and "new camera" on a trip that has such hazards to their well-being. I know, why have stuff if you don't use it. I also subscribe to that philosophy, but I also believe one should use the appropriate tool for the job at hand. That would steer me toward a ruggedized camera. Everyone needs one in their gear inventory anyway, so might as well get it now and be done with it. I heard the Olympus version lives up to its marketing hype...