The new releases of upcoming Rhino 5.0 WIP (on Windows) and Rhino 4.0 WIP (on Mac) both support Python as an alternative scripting language. This opens up possibilities of cross-platform scripting (Win/OSX/32+64bit) with plain text-based scripts. And if this opens the way to support Grasshopper on the OSX version, I can only encourage this evolution. Switching from RhinoScript (VB.script) should be reasonably straightforward. Some info on http://blog.rhino3d.com/2010/03/python-scripting-in-rhino-os-x.html and on http://blog.rhino3d.com/2010/03/python-for-rhino-50-and-os-x-available.html .