Yes, I learned a lot from this one as well - I kicked myself too cause I needed to do similar for what I'm working on.

What I did was I drew a rectangle and projected that shape onto the sphere then I extruded the side faces out, selected the outer curves and then networked them into a surface (the result shape wasn't planar so the extrudet didn't automatically close the front and back). The shell command does similar all in one swath - doh!

Granted, I needed outer shape to have more of an arc than to the inner shape but the shell command is certainly what I'll be using for some further work I need to do!

-Will