What an interesting video, Pete; thanks very much for posting the link to it. I have now watched it three times, and many of my initial questions has been answered as a result. I don't think it is ideal for my needs, but I can now see its appeal for certain types of riding and I appreciate the thought behind it.
I love learning about new approaches such as this. I have a number of reservations, but that doesn't mean I think it is a bad idea across the board. Rather, I think it would be ideal for some uses such a cross-country and downhill.
I'm not so sure about touring -- and especially for remote touring -- due the lack of field inventory in relatively remote locations. The system relies on some recent standards that may not have made their way to all outlets, and that could make for dicey parts availability. Coming from the days when a cog board was one of my most valued possessions for custom-building my own freewheels cog-by-cog, I worry that wearing out a single cog would require replacement of the entire one-piece billet cassette...but really, that has been the case for many years now and individual cogs are no longer available. For this reason, many cassettes are riveted together, amounting to the same outcome as this SRAM one-piece cassette.
I'll be following this with great interest, Pete. I can see some ready applications in the e-Bike market where a BB-mounted motor is employed. For that, the single chaining and wide-range cassette might well be ideal in hilly country.
All the best,
Dan.