There were several alternatives raised and discussed in that topic. You have to keep reading to find them all, as most of the discussion is about Windows. Here are a few direct entry points to starts of possible answers:
http://sketchucation.com/forums/viewtopic.php?f=18&t=16015#p138040
http://sketchucation.com/forums/viewtopic.php?f=18&t=16015&start=60#p440802
There is also john’s Add Icons SketchUp Plugins | PluginStore | SketchUcation