Hi Joris,
You know the sad thing is that I came very close to doing exactly that so thank goodness I realised the issues the NEX-7 sensor has with those wide FoV lenses. Whether it's lens design (symmetrical versus retrofocus) or sensor microlens design, or some unholy combination of the two, that is the cause of the border softness is way above my pay grade but for the sort of photography I enjoy, even at my very amateurish "happy snapper" level, the end result is "No Sale" as the old fashioned shop tills used to say if you pressed the right lever!
Back to WestCoast's point, I'll agree that I probably do get far too much fun out of the
techie bits but in the end I do know how to compromise and in this thread I'm sharing the journey. I am concious that there is a risk in doing so as we've had members over the years who've done similar hand-wringing with multiple posts in multiple threads and it can get irritating. Hopefully by keeping my thoughts in a single thread and by staying focussed on a particular requirement (downsizing but not compromising on optical quality) I'm avoiding being too annoying. I'd love to think that others on a similar journey might even find my ramblings useful but maybe that's a step too far!
I've spent a deal of time today looking further into the Olympus OM-D E-M5. Funny how you can miss things when cameras are first released. One of the attractions of the NEX-7 was the configurable twin control wheels and I've only now realised that the E-M5 has the same feature.
Will I always be "waiting for the improved evolution of what is available today" as WestCoast suggests? In answer to that I can point to my astrophotgraphy kit listed in my Signature below. That was a similar journey which started off very differently (at one stage I had an Astrophysics mount ordered and was considering a large Celestron reflector and a totally different camera) but over a period of a couple of years I finally refined my choices and ended up with the kit that actually is perfect for me. It will be the same in my search for a CSC. Selling old kit is far too aggravating so it is worth my taking my time and at the very least choosing the right system. When I invested so heavily in my Canon kit CSCs weren't even an option but now they are and with the steady improvement in sensor technology that has also taken place I really believe that DSLRs are about as appropriate to my needs as owning a Ferrari would be if all one did was use it to go shopping!
@Thomas I can't begin to guess why you haven't already done so!
Bob.