.. a second-hand APO-ELMARIT-R 2.8/100mm lens. I will play a bit with the lens on my current gear and if I feel comfortable I will make my final decision about which system to go to, if any.
For the moment I am very drawn to the SL camera, which has the correct adapter for the R lenses and provides the necessary in-camera corrections, at least until the range of SL lenses extends to a f.f. macro lens.
I have taken note of Jacob's comment above and so I have extended my search to other options, but for the moment I am starting my move with a second-hand lens.
Best.
Benjamin