Chances are that particular image wasn't created via Illustrator. I know Xara is great at complex gradient objects, as are many, many 3D applications.
That's not to say this couldn't be done in Illustrator. It would probably just take a bit more work.
The trick to odd shaped objects with gradient meshes is the start with a standard shape for the mesh, then alter it, and use several mesh objects.
Too many users think that mesh artwork has to be a single thing. It doesn't. Use multiple meshes to get the appearance you want, and overlap them. This somewhat limited thinking is similar to thinking that every drawing has to be created from one shape. Most use multiple shapes when creating anything. Meshes are no different.
In addition, since the implementation of opacity in mesh points, things got much easier because with opacity you can seamlessly blend one mesh object over another by merely setting a few mesh points to transparent.
So.... you overlay meshes onto other objects to create the appearance, adding mesh points as needed. By starting with a rudimentary shape for the mesh, you don't have to deal with those wild, uncontrollable, mesh handles and points you get when adding a mesh to a complex shape.
... I gave up on this once the (wonderful) Adobe lack of accuracy reared it's head.... but here's a sample...