Thanks guys for all your replies. Really more helpful than I hoped for.
- Ade-oh -
You are pushing where it hurts, but you are actually right. I need to keep focused - I actually want to look for a camera + lenses that work well enough - after all I want to project the slides and not pixel peep them. I have 4x5" for that purpose
- SteveM -
Yes - I though of projecting 6x6 slides, but apart from large and rather rare 6x6 projectors (I have seen very nice automatic Hasselbald for some 1400 euro

, though I know that there are cheaper) the point here is that I do not tend to shoot "travel" pictures to show to my family or friends with my Mamiya 6. As this camera takes a bit more time to make the shot (the metering is PITA to he honest, I tend to use hand hold meter recently) I would not really be able to put a slide show. I would proably have to go for 645 SLR to do so and then the camera gets large and heavy and less pleasant to carry (but as I said - the soft spot for Contax 645 is there - but that would mean to sell the Mamiya). So for now I consider only the small format option. I actually tried to find some 6x6 slide viewer, but there is one old Patterson model that that's it.
The OM2n are really cheap, have the best viewfinder (even larger than OM-4 Ti), but the faster wide lenses are rather rare and not cheap at all. On the other hand FE2 is priced reasonably, the finder is size vise comparable to my wife's Minolta 7 (which I plan to use with 28/2.0 and 50/1.4 in the next days to get better idea which lenses I want) - which is nice enough, so to say. But I want manual focus and AE.
I am surprised to hear that VC did the 40/2.0 in OM mount too. Actually - is there any difference between
SL and
SL II lenses?
FM3a would be nice, but costs more. The same is true for the new VC lenses. If I were to go Nikon I would consider the 35/2.0 AF D wich reportedly is a better performer than the AI-S version (which is older).
I had a look at Contax but the lenses are really on the large heavy and pricey side. So maybe next time.