I don't know if it has been discussed much but there are a few cases where the max capacity layout can be of great use.
- emergency evacuations. there have been a few major evacations where there have been people cramnmed on to 747s (seen some threads on here about it). 800 seats, fill the ailes, in effect no baggage. A few in this setup could do a great job.
- i cant remember the name, but isnt there a religious gathering in the middle east somewhere, pilgramige to Mecca?, where they have masses of masses of people there, transport to/from this event could be another good use.
First thing in running these type of flights as normal service is making sure the airports served have the capacity to handle all those people. The idea of cramming close to 800 people into a departure area for a period of time is rather frightening. I'm sure they will figure out ways to do it, but organization is desperately needed
Hopefully the LCCs will be encouraging people to not bring checked luggage...imagine the line for that...aye aye aye.