It's a neat trick, what Leica pulled. For 80 years, they built a reputation — 'the Leica look,' 'the glow,' 'classic photojournalism' — what have you. A Leica 'signature.' Then, when they abandoned film and went digital, they managed to get people to define the new digital look as 'the Leica look.' Genius. The old look was Tri-X and D-76. The new look is color and grainless.
Digital is wonderful. For many things. But, it's also an equalizer. That part is sad. My interest in photography began with fashion, and until the digital changeover, you could identify any of the major fashion photographers' work in magazines with a quick glance. Everyone had a signature. Whether they were shooting in color or black and white, there was a commonality to their images. Now that everyone's shooting the Hasselblad H system or the Canon 1s, it's all gone. Can't tell one from the other (except for Terry Richardson).
So, anyway.... It seems to me the thing that made Leicas wonderful - that vast catalog of imagery stretching back so many years - it wasn't about clinical sharpness, maximum resolution, or grainlessness. Sure, the lenses were some of the best. But, with Tri-X and f1 or 1.4, so what. None of the most renowned rangefinder fotogs had that 'ultimate clinical precision' thing going for them. And, so, now, when Leica's touting all their tech achievements, and still resting on the laurels and legacies of people like HC-B, i'm wondering how it all fits together.
The OP seems like he wants a Leica because it's a Leica. Not because it actually fits what he wants to do or how he wants to do it. I used to be in the same camp. I tried M7s on two occasions, and an Ikon after that. I had three R cameras. And, all of them were disappointing, in some way or another, despite the excellence of the (M) glass.
A D800 might feel 'plastic-y.' Compared to an M6. So what. 99% of the pros making a living with photography are somehow getting by with plastic. At some point, we have to get over ourselves. There's a reason pros don't use Leicas for professional work. And, there's a reason why the dilettantes use them only "for personal work, when i can take my time and THINK."
Get a D800. Or a 5DIII. Sell it a month before the D900 or 5DIV comes out. And, repeat. Stay at the top of the tech curve so you never have to feel inferior. You'll probably have to stay out of forums like this, where the guys with the digital Leicas will constantly tell you their cameras do magical things, despite the old, low-spec sensors.