I took my new coiler swallowtail-ish AM (bought secondhand from tim) out for the first time last week, and it rails! Carves like a dream, soaks up chunky Oregon snow, and floats great in the pow. This is my one-board quiver for Mt. Hood, no questions asked. It's a pretty normal AM shape- 10.5 sidecut, 21.5 waist, but has a triangle maybe 8 inches deep cut out of the middle of the tail.
This got me thinking: is there any downside to a tail cutout, assuming you don't mind not riding switch? Are there durability issues? I'm not worried, since I'm a light guy, but it cranks the ride up so much I'm curious about why we don't see it in other boards.