People are over reacting with this shutter shake issue. To get the most out of the A7R you need :
1. The best of the best glass available.
2. EXTREMELY accurate focus
3. No camera movement whatsoever (in your case a strong tripod should do)
and THEN you can factor in image degradation due to shutter shake which is close to none (I have yet to see it even tho I shoot at those "dreaded" shutter speeds).
The fact is even if you get to actually see some shutter shake it'll only show up if you do an insane crop (might as well consider you missed the shot at that point) or print extremely large and examine it with a loupe!
I don't know what kind of work you are looking to do but to even consider shutter shake on an A7R as an issue you have to be part of that 1% elite photographers out there for whom every freakin detail matter because they're paid thousands upon thousands for their work.
cont.....