Perhaps it is cost effective, but using adapters would presumably create another port for entry of dust and another connection allowing for more play in the mount. These are only assumptions on my part, I'd welcome feedback on this issue for those of you using adapters for third-party lenses.
Loosely constructed mechanics are one of the primary reasons I don't like the Nikon options. Also, full shifts get well outside the sweet spot. Lloyd Chambers makes a point on these issues in his lens review. The Hartblei T/S lineup eliminates these issues. The 40mm/4.0 is terribly large, true enough, not to mention the expense! It is my choice for wide angle, although it is clear others desire wider. I remain very satisfied with the Hartblei 40/4.0. The integrated tripod collar makes for possible bidirectional, parallax-free shifting, and due to the massive glass diameters, no vignetting or softening when fully shifted. Last but not least, what is claimed to be 200 line pairs/millimeter resolution makes this option all the more desirable.