Final question is, even if you get all this gear. Are the images at the widest angle as sharp or sharper than those you can get with a DX system?
I d like to know this answer.
For me if the FX format is better I will buy a D800. (Sigma 15mm)
If Dx is better I will wait for D400 (tokina 10-17mm) or 7D markII (Canon L 8-15mm).