I do not know, but would venture that prints from all top notch glass would be to all intents and purposes, 'all great'.
I would hazard a guess and say that Zeiss, Leica, the best Japanese pro-glass will all be similar and the variation within a range will be more significant than between ranges. By this I mean, all ranges have their better and less good lenses and this might be more worth worrying about. I also get the impression that Leica quality control within batches is second to none.
If you can afford it, great, but I would not sacrifice much by way of photographic opportunities to get the most expensive glass when you could get something to all intents and purposes just as good for less AND do a photo tour or three. This is esp the case if you are shooting mono.
Zeiss glass for the Contax SLRs seems much cheaper than Leica for example, but just look at how much cheaper Japanese L glass is, esp at the wide end! Also consider utility. I was considering buying into a rangefinder system for work in afghanistan, but realised that a lot of the shots would be at the longer end and speed really mattered. The less time spent squinting thru a finder to get correct focus, the better! I therefore decided to expan my Canon system with some L glass. I will just have to deal with the greater size of it all. I really wanted an RF to be the answer and dont find I get a glow from owning my EOS syst, but being honest it was the right choice. If your work is handheld and would benefit from blistering focus, I would venure that Japanese AF ALR would be the way to go. I am sure that Leica primes would marginally better Canon L glass at wide apertures, but I am certain that I will get more perfectly focused frames from my Eos system, esp when it comes to the tele end and miss less fleeting opportunities. When I have only a few seconds to grab the shot (whilst trying to have eyes in the back of my head) speed is a more important factor.
At a salgado exhibition, I was amazed by the prints. He uses Leica SLRs in the main, but (aside from his talent) it was the dynamic printing that really stood out from the technical standpoint, not the 'resolution' o 'microcontrast'. The odd image was a touch soft here and there and those from heavily enlarged TriX lost detail to grain, but WOW.........and it was not because of the glass but everything else.