From reading the recent post, it appears like we have come to the conclusion about how and when optics with wide views will stretch the image and give inaccurate renderings. Lets get back to the point of price; I feel what I said earlier is still right, you would be better off putting the money into a MF system then getting these lenses. Lets look at two options for a system.
For about $8500 you can get a:
Canon 1D, 21 mp recording at 14 bits per channel, 10.5 stop range
the new Canon 24 ts
For around $16,000 you can get a:
Alpa 12max
Schneider 35mm
Leaf Aptus II 5, 22 mp recoding at 16 bits per channel, 12 stop range (and unlike Phase One's entry level backs, this one still has a large sensor)
Now as far as I see it, aside from saving you 8000, the DSLR system offers you a lighter camera easier to transport, automatic settings, and the ability to use very long lenses. Aside from the last one (and the saving of 8k does sound good), the other two I do not care about. You could also make the claim that it would be easier to find someone to look at your canon if need be.
The MF system over the DSLR offers greater optical resolution, a much larger range and color gamut (remember bit and stop growth grows exponentially) giving you more freedom in PS and more lush transitions, the ability to shift on both axes, sturdier construction, levels on the camera, etc. Also, when the sensor becomes obsolete, you do not have to replace the whole body, only the back. Last, the pixels on this back are larger in size then on the Canon, decreasing the chance of getting apo-chromatic aberrations (it is Schneider glass though so you would not have to worry about it anyway). Although you do increase you chances of getting morie by going with an entry level back, but that would not be any different then the Canon.
You could even lower that price by about 2500 and get a Cambo Wide DS.
Now 8000 more is a large sum, but if you are spending 8500 anyway, why not just put out the extra to get a system better equipped to shooting the subject?