Looks like the 6D may not be so bad after all

[chadders]

4000€ in my wallet want to be spent...

Does anybody know. if the AF of the 6D is FAST too, or just accurate at low light?

How can someone know? 6D is an imaginary camera for now. Although I guess Canon cannot tolerate postponing it for many months (D600 being the reason. Ins't competition nice?)
Are you starting from scratch?
In that case you could go for the kit 5DIII and 24-105 f/4L IS.

It is possible to get it in Europe for 4000 euros

Not true, i tried it on the Photokina there were 6 6D's to try, also here inteh Netherlands there are pro workshops where you can also try the 6D. And yes i know for sure it is there and yes i really had an 6D in y hands and played with it for almost one hour!

Presumably you may be in a position to answer the questions raised regarding the AF, since you say you played with it for almost an hour.

[jrbdmb]

It looks like noone wants my money unless I give them ALL of it.   

I think you nailed it.

Between an overpriced 5DIII and an underspec'd 6D, I'm choosing ... to spend on neither.

Well, at least the problem with the 5d III can be corrected over time, and at around $2900 new this issue may already have been fixed.  Fixing an underspec'd 6D on the other hand ... not so easy.

[Marsu42]

Well, at least the problem with the 5d III can be corrected over time, and at around $2900 new this issue may already have been fixed.  Fixing an underspec'd 6D on the other hand ... not so easy.

But it is - sell the 6d for €1200. The 6d as well as the 5d3 have weaknesses, obviously the 6d more than the 5d3, and "underspeced" for the 6d is only related to the competition (d600) and the current price. Just like the 5d3 is also just another camera and there are better current models (1dx) and there will be newer replacements to come, maybe sooner than later.