Which lenses for architecture?

I'm going to do so some architecture photography, probably for publishing. So I need wide angle sharp optics. What do you recommend? 12/2,0? 9-18? 7-14? Even Samyang 7,5, de-fished? Is there any tilt-shift option at all out there?

I have done some work of this kind earlier mainly wiith a 40D and Sigma 10-20. This is really not the best you can get, but quite okay if you don't make the pictures too big.

Now I have an OMD and the widest lens I have so far is the 12-50. I feel it may be wide enough for most situations but not all, and probably not sharp enough.

I'm not sure I'll get paid, so budget is a concern. 7-14 has twice the price of the 9-18, but is it two times better? Samyang 7,5 is cheap and said to be sharp, and you can do "defishing" f ex with DxO Pro (wich I have), but is it usable in practice for rectilinear photography?