Oh my goodness!
I've just speed-read through this thread and several things jumped out at me.
1) The prejudice against ATR72/Q400 or indeed any turboprop, made me want to scream-vomit
2) The short hops mean inter-island a/c barely reach higher altitudes for (jet) engine cooling purposes, but did anybody mention they also fail to reach the zone where (jet) engines are most efficient. If that doesn't suggest turboprop as a solution, I give up.
3) I loved the idea that a fleet of 20 717s was "just right", whereas 30 replacement Q400s was a "massive fleet"
4) If you think I am prop-crazy, note that I also liked the concept of using smaller models within the 737 family in order to benefit from less stressed engines.
5) Would the above idea also work with the current (larger) model 737 family, but employ a less dense ("premium") seating arrangement and reduced cargo capacity, hence lower take-off weight, again allowing the engines to operate at lower thrust settings throughout the range. (Yeah, I know, like that's ever going to happen...)
6) If the 717 is the optimum solution by virtue of the RR BR715 engine, what other a/c use this engine? The Rekkof/Fokker F100 was short-listed for it at some point, but that program still needs a launch customer.
Or, since Bombardier already use it in various forms (incl the latest RR Pearl version) on the Global Express family, it can't be that much of a leap to adopt it on the (much maligned) CRJ-1000.
I suspect someone will flag up a shortfall in freight capacity, to which I would add a dedicated ATR-72 freighter to the fleet as a solution; it's not like the cargo will complain because it's a stinky old turboprop.
7) I love a nice ride on a boat, watching the whales and all that palaver, but I accept 3hr ferries across wild ocean is probably the best solution for all this cargo that currently flies around at 500mph when in reality it is rarely that urgent (medical supplies being a possible exception).
8) And finally.....Engine cooling; what happens when any a/c flies through a rain shower? I think I know the answer. So how about a (gentle) water spray directly into the engines whilst they are idling on the ground. If those engines are not certified to cope with this "sudden" temperature fluctuation, I don't want to be flying in one on a wet day....
Nothing to see here; move along please.