This is my home brewed holder or "rig" for my Cokin X-Pro filter system. There is a lot of misinformation in Nikon centric forums saying that it is not possible to use ND or ND Grad. filters with the Nikon 14-24mm lens. This is not the case. The above solution is for my Nikon D700.
There is no vignetting at 14mm if I only use one filter and 17mm if I stacked two filters together (Cokin X-Pro ND4 and ND8 Grad. filters).
Also most of the DIY solutions that I have seen for the Nikon 14-24mm lens are for the "DX" or cropped sensor Nikons, e.g. D300, D90. Not suitable at all for a "FX" or full frame DSLR, e.g. D700, D3 or D3X.
Cokin X-Pro Filter Holder
Cokin X-Pro Universal Adapter
Home brewed (DIY) filter "rig"/adapter