"Stand-alone" works for what you want, but in the sense that you want it uninstalled, not installed.
And the fact remains that what you want is impossible, because Apple no longer packages Safari as a stand-alone app; it's available only as part of a new OS X installation or, as you've unhappily noted, from Software Update.
(Following up on ganbustein's question, I'll ask why you want to keep Safari 5 when you can run Safari 6, particularly in view of your dislike for v 5?)
Aside: Hmmm... I wonder what you'd wind up with if you ran, say, a Lion installer through Pacifist and extracted Safari to your desktop?
