Architecture assignment: D3 + 24/3.5 PC-E or D800 + 12-24/2.8???

It is December, time for a last bold move, regarding an important architecture assignment. What to buy???, a D800 or a tiltshiftlens 24/3.5 PC-E

Current gearlist

D3, D700, D200

Nikkors: 70-200/2.8VRI, 24-70/2.8, 12-24/2.8, 50/1.4, 35/2, 70-300/4.5-5.6

Sigma: 105/2.8, 180/3.5, 100-300/4, 20/1.8, 10-20/4-5.6DC

If to buy a D800 I would use it on the 12-24/2.8

If to buy a 24/3.5PC-E, I would use it on the D3

Considering a tiltshiftlens: does it improve in image-quality on a D700, or has the D800 that much more pixels that it can easily outweigh the D700-file regarding perspective/distortion manipulation in Photoshop.

I also do a lot of landscape-photography so I am tempted to go for the D800 instead of the tiltshift 24/3.5PC-E. But Architecture pays the bill more than landscape does. Yet again, the D800 would be a perfect fit for the 12-24/2.8.... that would give me three bodies and three 2.8 zoomlense of the holy trinity. The D3 for the 70-200, the D700 for the 24-70 and the D800 for the 12-24/2.8.... no more need to switch lenses, saves me the dust :).