Well, some people asked me to report back with what I got, so I will!
I ended up getting a Samyang 1.4 35mm.
It was cheap, but can produce amazingly sharp images. Magic? Yeah I reckon it might be, time will tell.
It is probably L prime quality, BUT, it is manual focus and no IS.
It is a whole different ballgame, in that it needs to be kept very steady due to crazy narrow DOF at 1.4, and again due to narrow DOF needs liveview to get focus bang on.
But, as it happens it is adding some fun to my photography. Getting a good picture is no longer about pointing an IS lens, autofocusing in .01 sec and going click. It takes a lot more time to get a good pic.
Not that I want to use it all the time, but it is the difference between throwing a stick of dynamite into a pond, or setting up the bait and tackle just right to get a fish.
I would never had got this if the 24-70 had been IS, but funny the way these things lead you....