I love it -- especially all of the '-' lines in the patch! Good work. Is it conceivable that a Windows XP user would have that privilege (and thus would have access to a non-functional os.symlink function)?

One thing I particularly like is this provides an interface (os._symlink) that developers can use if they expect privileges to change at runtime, but for the majority of use cases, the os.symlink interface is otherwise largely consistent.