GIMP Script: Mercator to Dodecahedron
Though it may not be particularly useful, I have written a script for GIMP which will map an Mercator projection to a result than can be printed, cut, and folded into a dodecahedral "globe".
The mapping is not perfect, since the faces of the "globe" are flat, but it generally achieves the result I wanted. Note that the original projection should have a 1:1 width-to-height aspect ratio. The actual width of the original does not matter other than larger projections will result in sharper results (the following image used an original projection that was only 320x320 pixels).