Just some quick notes here on depth of field. I am not going to ponder the technical aspects, just more or less how it appears to my eye. I think the easiest and most effective way to treat it, is as if the lenses were available to you on 35mm. I don't think you will have much difficulty getting wide depth of field out of the wide lenses -- 35mm and wider. These lenses are already considered wide angles on 35mm, and provided you stop them down a bit and don't focus on things that are extremely near the camera, they will provide you with very generous depth of field. I find that at f/11, the 35mm S lens provides extremely high resolution over the entire image, near to far, and it also produces beautiful ray-like starbursts in the specular highlights.
Like this:
or this:
I suspect that you will find more of an issue regarding depth of field with the longer lenses. There is significantly less depth of field in the 70mm lens than there would be in a 50mm on 35mm cameras. The 120mm macro is of course even shallower. But assuming you have enough distance, they still show good DOF. This image, for example, is printed at 1mX1.5m and looks just great. You can see the snow in the foreground is not completely sharp, but the streetlights are good all the way through. The fence at the end is not sharp per se at close inspection of the huge print, but from a normal viewing distance everything looks very sharp. It was taken at f/11 with the 120mm lens.
I find that f/11 to f/12.5 seems to be where diffraction starts to come into play. F/16 is still sharp, but noticeably less sharp (or maybe it's just less microcontrast?) than f/5.6 or f/4 where a lot of S lenses hit their peak contrast. f/22 is noticeably softer, and I don't think there is much reason to use it other than in incredibly bright situations where you want a slower shutter speed and don't have an ND filter...i.e. not often!
Overall, though, I get this nagging feeling that your technical requirements would be met just as well (or maybe better) by the D800E, and that your interest in the S2 is just that very typical "grass is always greener" equipment anxiety. The S2 will not make your work better, at least not in a way that will make people stand up and take notice. But if you are happier working with it, and you feel it improves your work, let's you make what you want to make more easily and enjoyably, then it is money well spent! It did that for me, and I think for Kurt, Marc and a lot of other S2 users. It is a hell of a camera, but don't think for an instant that if any of us had "just" a D800E, that it would be holding us back technically! It's not that these differences aren't there, it's that they are subtle.
I do think you are absolutely on the right track to chase the S2 lenses though. They are the biggest strength of the system. I think Leica basically sat down and tried to make the best lenses they possible could, designed for a larger, high MP sensor, and then made the body fit the lenses. The only point I would echo would be the one regarding not waiting for lenses that are not already out. If you truly "need" a 14mm equivalent, the S2 is not for you. They will never make it. Or at least, I can't imagine why they would. I would not be surprised if the 24mm was the widest they make. In fact, I would hope they would stop mucking around with super wides and start making something normal! How about a 40-45mm for heaven's sake?
Enough ranting...
