If you go for the Canon option don't forget though that Canon's base ISO is still not that great (shadow noise!), it is worse than your DM22 for sure. If you do a lot of shadow pushing in post-processing it can be a problem. You can shoot HDR to work-around in difficult situations of course, but then you lose workflow speed. Being careful to expose to the right to make use of every stop in the camera is very important with the Canon.
The shift and tilt gears on the TS-E lenses work alright, but it's far from the feel of a real tech camera controls.
Anyway, I sure would like to see yet another tech cam user, but if you're on a budget and do it for normal commercial work I think it will be hard to rationally come to the conclusion that a MF tech cam is the better choice for the use case you've presented.
Arca-Swiss RM3Di or an Alpa with Rodenstock Digarons and an IQ160 would blow the Canon away of course, but it is a major investment to make and typical customers don't need that quality.
When we instead compare the DM22 + Cambo + Schneider Digitar 35XL with a Canon system, the tech cam will still give you an edge, better colors and dynamic range from the sensor, distortion-free lens (corner sharpness after shift I don't dare to say is better though, neither are perfect and I haven't seen an A/B test), but the image quality advantage will be small (unless you are an MFDB CCD connoisseur
) and you need to put it in relation to the practical issues with the long shutter speeds and lack of live view, plus what I assume the higher price, although the 5DMk3 plus a TS-E 24II is not cheap either.
Oh, 22 megapixels without AA filter can be an issue concerning moire when shooting architecture. But I guess you are familiar with that already. Higher megapixel digital backs usually has less issues. I've noted a difference between 22 and 33 even, but I think it is managable. It's probably worse with fabrics than with architecture.
If you stitch indoors, note that TS-E shifting will move the lens element rather than the sensor which may lead to parallax issues, although there are some custom lens mounts for that if you need to work around it.
Here you have an example of the TS-E 24II + 1.4X III extender combination used in a professional setting (goto 02:00 min):
http://www.youtube.com/watch?feature=player_embedded&v=5HkrjQkanSw