Graeme, that's a good kit, indeed. My standard 35mm film kit is only a bit different... it is an FM2N, a 24/2.8, a 50 (1.8 or 1.2 depending on light), and a 105/1.8. When I do carry a zoom, it is an 80-200/2.8. For my taste the 85 is too short for the prime kit- I prefer the 105.
IMHO the $$$/MTF ratio for the Leica R lenses is offscale and not in any way comparable to what the Leica RF lenses deliver. Maybe not so much any more, but if were disappointed with the Nikon lenses, I'd go for the Zeiss ZF primes.
The contax RTS systems interested me greatly for a while. I just couldn't quite make out with the bodies.