The problem with this is that according to the known market research less than 15% of all interested airlines want more than 250 seats, while over 50% asked for less than 200 seats.
At what density though?
JAL has only 186 seats in their 787-8. https://www.seatguru.com/airlines/Japan ... 7-800.php#
AA's has only 102 seats in their transcon A321 fleet.https://www.seatguru.com/airlines/Ameri ... 1_new.php#
The numbers we throw around for consistency is 28-30" pitch full economy cabin. This is simply for comparison purposes only. 2 class and 3 class cabins will have a significantly lower seat count.
Usually the longer the flight, the more spacious the cabin will be with a larger percentage of the cabin dedicated to business class seats. Let's say the
797-8/9/10 has 250/300/350 seats all economy. In real life that will probably end up being 150/220/290 seats. The 787-8 being longer range will have a huge portion of the cabin dedicated to premium seats. Where as the 787-10 for short flights would probably only have a couple rows of slightly wider recliner seats.
Passengers on average are less likely to upgrade to a business class seat on a short domestic flight.
My comments were based on this:
In summary 120T maximum takeoff 70-75T OEW
797-8 250 seat economy, 200 seat 2 class, 5000nm,
797-9 300 seat economy, 240 seat 2 class, 3500nm,
797-10 350 seat economy, 280 seat 2 class, 2000nm,
The available data show little support for the medium variant and nearly no interest in the larger version.
If we go with the EASA recommend 105kg per pax, the larger version would need to carry 37,8t just for the pax and their bags. Which means that with a 75t OEW they would have a whooping 7,2t for fuel, crew, reserves and cargo. I do not see this sell at all.
The short version would need 26,25 t only for the pax, leaving it with just 23,75t for fuel, crew and cargo. That is just 10% more than A321CEO with 230 seats, but it needs to fly 36% further.