Glad to see progress on the dual-motor and hope that Rivian is also making progress on bringing the production of all of their motors in-house. It's great to see vertical integration making a comeback, for many reasons, chief among them efficiency. Folks familiar with automotive history will recall that Ford production was much more efficient years ago when its gigantic River Rouge plant was not only the location for final assembly, but also responsible for making many of the needed parts.
On a somewhat related note, I want to throw something that is pure speculation on my part out there. I have been asking CS about the Max, errr "Longer Range" option for the R1S for many months now, with no real response other than some version of "we're working hard on that and hope to have more information in the near future. Could it be that Rivian has thrown in the towel on a larger battery pack for the quad-motor R1S and is now planning on introducing as a option for the upcoming dual-motor variant? I think there are some clues.
Rivian quietly took the R1S Max off the table, removing it as option from the configurator more than a year ago. While Rivian continues to say that they hope to offer a "Longer Range" R1S, they have not provided any real information for many months. That could indicate that it has proved more difficult than anticipated in figuring out how to get a larger battery pack into the existing quad-motor R1S, something that is probably unsurprisng given the SUV space constraints.
Rivian has to do a fair amount of design work, both engineering and manufacturing, to adapt the skateboard platform, and many related components such as suspension, steering & wire harnesses for the dual-motor variant. It may make sense to add the a larger capacity battery as a clean sheet design exercise for the dual-motor R1S rather than continue wrestling to retrofit the larger battery into the already existing (and in production) R1S.
Emphatically not saying this is the case, just reading the few tea leaves that Rivian has provided and hazarding some guesses.