Hi AndrewG.

Maybe something like this ?

Here's the 3dm file : http://take.ms/DOSrB

And here's a video capture of Moi's viewport : http://take.ms/RGhbn

To do that model I've used one of the many possible ways : Trim, Blend and Project with some curves.

I'm going to show you a simple example in a little video tut.

Bye.

Marco (mkdm)