Over on Vimeo, commenter LBX (check out his multiple texture map vids) suggested an alternative approach to placing objects on the polygons of a sphere. (See my ICE modeling posts here and here.)

Here’s the ICE tree (which is on a point cloud of course 😉 The use of PolygonNormals and the sphere radius is neat.

To deal with more general geometry, I think you’d need to do something like this: