: I don't have pictures yet, but imagine perhaps the old F-111 swing-wing
: fighter bombers. The wings' surface area stays the same, but with them
: extended, more drag profile is created, while the wings in the swept back
: position act more like fins.

: This should make the system more efficient by creating less drag, yes?

This is basically what Necky is doing with the drop skeg on the Elaho. It's essentially a section of the keel that drops down. Now, if they would only give it a nice wing-shaped profile...