If they can sell them, there's a market! =)
For the scan backs, sure. There are a lot of reasons they're good. For studio work, you have full view camera movements, and digital capture. It being digital, you're working with a first generation image than a second gen scan. You've got a lot better control over exposure, and no grain. Check out the info here: http://www.betterlight.com/why_better.html
. I realize I'm just throwing marketing links at you, but I honestly don't know enough about scan backs. I have used them a few times, as well as multi-shot MF backs. Not too useful for what I do.
If you're an architecture shooter, or a tabletop product shooter, these products are great.
As for the Gigapixel project, that isn't designed to be a commercial project. However, reading about it is very interesting...and there are prints that have been made from the images that are astounding (from what I hear).