Have you ever seen the 757-300? I deadheaded on that once from Florida to DTW and it was incredibly packed, maybe 220 seats with a first class section. It took forever for the pax to get off the plane. I hear that one has the best CASM around, just a 757 stretched to the max. And what about all of those 737-900ERs we're getting starting next year? Those will have great CASM too.
As far as your 717s go, if Boeing got a good deal, they would take them off of SWA's hands quickly. That may be one way a certain airline can take another one out of certain markets, albeit smaller markets. I bet GK's statement has perked the ears of a few CEOs, or at least one.
Godspeed!
The OYSter