Thanks, guys.
#deejjjaaaa: I'll check out the ML firmware for sure. However, I think that solution may still be a post-shot check. I've still to explore the various metering modes.
#Jim: I probably should have called shadow clipping by another name. I assume it is as you say, where the camera software detects the photosites that are not receiving enough light to lift the output values above a base sensor SNR threshold. So the camera highlights those outputs (data pixels) as blocked up shadow. In high contrast scenes you can see shadow and highlight warnings at the same time, of course.
I've seriously considered both the A7 and A7R and each time have walked away. I really wanted to put together a good system around those camera but couldn't.
I considered using Canon L glass with a MB IV adapter for telephoto and ultra wide angle zooms for landscape work, and some fast manual focus primes for street and walk about (Canon FDn, Voigtlander, etc) in crop mode (A7R) to get smaller files and improved IQ. However, the R just isn't flexible or reliable enough for me to make that commitment. Then there is the issues around adaption, shutter vibration, raw compression artifacts, not so good high ISO performance compared to the 6D, and the lack of image stabilisation on those primes (not all focal lengths I wanted to use were fast enough either at >f2).
As I consider the preferred system for me I begin to go down the potential of an E-M1 in a body large enough for full-frame IBIS and lenses without the added bulk of IS. The next best thing is the A99 but I just cannot justify the excessive pricing of the CZ glass, and there isn't enough Sigma Art in the range (which still has IS built in). Yet, the A99 is a far more mature platform compared to the A7 series. Although, the goals for each are also different and the A7es are more of an experiment in that regard.
I thought of going with all-Canon glass with the A7 with the option of replacing the A7 with a Canon mirrorless in the future. But the glass is too heavy for the smaller body for anything other than tripod use especially when looking hard at the weight and size benefits of mirrorless systems.
Sigh. We are in a transitional phase and it's going to span a couple of years most likely.
The whole move away from the awesome E-M1 started when I considered spending money on the new 40-150mm f2.8 PRO tele-zoom and reviewed the senor size.
I've digressed a bit so returning to the topic I will continue to consider a dual system option if I can't put together a single system that covers my preferred handling. However, I'm not sure that I can find a small mirrorless with as good low-light capability as the 6D!