Since the topic is interesting and I have done / will be doing some work using these techniques I thought I would speak up.
In no particular order:
First: Ebony's are great quality and not expensive given what you are getting. I have the non folding sw45 and used it extensively. It is fast and a joy to use (the smell of the leather bellows alone makes me feel good).
The poster that said that it cannot do flat pano's because the back has only rise is incorrect: simply tilt the tripod head on its side and you have your back shift ! But I wouldn't dream of using a traditional view camera for a digital mf back. Perhaps the arca 6x9...... but I would prefer to go to an Alpa or Cambo and do it properly, especially for the wide angles..... And also: yes, there is the old saw about how taking a long time to consider and compose leads to a different type of image- but as important sometimes is speed- the fast set up and shooting of what is going to change 2 minutes from now, or where you might get kicked out if you are there for more that 10 minutes - or getting more than one shot an hour. This seems to be a frequent occurrence in my experience.
As to the question of whether a digitar lens would give better results than a 90 canon tse on a Canon 5d2 I can say I wouldn't even bother testing this. The 90 tse is perhaps my sharpest lens, the results from it are astounding, the images need hardly any sharpening, unlike my other lenses. Then there is the convenience of a dedicated optic that automatically sets aperture, and probably cost much less AND has no klugey mounting system. If I was comparing absolute quality of a digitar on medium format versus the 90 tse on a Canon I'm sure the digitar would be better, but then you have to factor cost, ease of use, weight, speed, usable ASA and a host of other factors, including possible focussing issues. Wide angles would be another story, but again, I think the new 24TSE, which I just purchased and have begun testing, is a really great optic, probably the best wide canon has ever made.
I will be using the new 24 TSE (and the 45 & 90 TSE's) to do flat stitching and, if necessary rotational panos. I have done a large number of stitched shots in my career, with film and digital. Naturally I prefer flat when at all possible because of less perspective distortion (significant if you shoot architecture). I notice that the above pano rig shown is using RRS equipment. I will be ordering an L bracket for my new 5D2 tomorrow as well: I will calibrate a side slide on the clamp to maintain as close to exact camera body position when I shift the lens (shift lens to the right, camera same amount to left, then opposite for the second exposure). These L brackets are a great solution (I used one for my x-pan) for rotational panos as they can position the camera vertical over the rotation point of the head. One can eliminate the second stage rotational platform above the ball head if you have a leveling center column that can be had with a gitzo carbon fiber model (and perhaps other tripods),
As to the question about what is more "artistically" valid technique (1 shot, flat or stiched) I will add a few things. There is a difference between seeing / composing the entire image on one glass image and shooting it in one shot as opposed to compositing the image from a number of shots on a computer no doubt. Many many pano's, including flat stiched pano's, suffer from digititis, that unreal look (and I have done quite a few myself!) that is due to a variety of factors. In some sense there is a fracturing of reality when these techniques are used, starting with the element of time and so on (and this is a benefit if you are after this quality of "unreality"). As a side note, the lust for super high resolution tends to result in oversharp images that lack real atmosphere- just something to consider......
Stitching however allows one to make images that otherwise might not be possible, and that is a significant thing. There are situations where you just would not be able to make an image without stitching and especially when you shoot architectural scenes and interiors like I do there are some images that can only be captured by stitching. In these cases there is often distortion if you combine radically different perspectives. This is definitely constructing an image that could not be otherwise captured.
As to previsualizing an image that you will assemble later: yes, one can to a degree. I have done a lot of work in the old days shooting fuji 6x9's for interiors and architecture: and learned to capture what I was after quite well, even without being able to precisely frame it. Then there is the comment from (I believe) Friedlander: I take pictures to see what things look like when photographed.
To each their own. For myself, I fall into a middle category. I want high resolution but I want it flexible and portable as I travel a lot and sometimes time is limited. Digitar lenses are the solution for the highest quality on medium format digital backs when you have lots of time, static subjects, or are in the studio- plus have a big bank account. Otherwise, stitching 21 mpx 35 camera images with tilt shift lenses, carefully handled, can give excellent results, as can rotational panos with sharp lenses.