Well, that's not JUST an internally geared hub, which isn't that uncommon, nor is it just any old chainless setup (much less common, but still findable). Nossir. That's a frigging SHAFT drive setup, which is absolutely not common. It's a very old concept, and many motorcycles use it, but bikes don't very often at all. My understanding is that shaft drives lose you at least 10% on your efficiency, which is a ton on a bike. Nothing beats a chain for efficiency, except perhaps a carbon belt drive, which is the chainless setup I expected to see when I scrolled down.
A quick note on belt drives: They are clean (no oil required), they are quiet, and they last longer than chains. They're wider, though, because they have to be wider than a chain to handle the same amount of torque. That makes them a little harder to line up left/right wise, and they're much less tolerant of being out of alignment. They're also solid with no removable link like a chain has, so since you can't "break" the belt like you break a chain to install it, you have to "break" the bike frame. Think of it as the magician's trick with the two solid steel rings that he suddenly links together. Your frame has to have a split in the rear triangle to slip a belt drive in there. Thus, you ain't tossing a belt conversion on just any old frame. You can have a segment cut out and replaced with a welded-on coupling that screws back together, but who's gonna pay for that? So you tend to need to make the frame with belts in mind from Day One.
A quick note on IGH's: Shimanos are the most common, and for good reason. They're about the same price as Sturmey Archers, but they're more sophisticated on the engineering side (a good thing - more robust, easier to shift, last much longer with no maintenance) and are made better. Other options besides those two are expensive and for specialists. Rohloff is the top of the pile (I want to say just the hub is $2k?), and Nuvinci is midway between "consumer" and "touring pro nerd". Of the Shimanos, the one you get tends to be dictated by how wide your rear dropouts are on your bike frame. The 3 speed Nexus is something like a 120-125 spacing, and the 8 to 11 speeds are 135. So you can't just drop whatever you want into your frame.
