What are you talking about? Have you checked the i386 folder? There are more then 1200 files having 5503 in their version number, and in the same time having a different build number (5.1.2600.5503, 5.2.... , 6.0.... ) Maybe this is not the final one (even if it is already "shared" as one), but it's almost there. And nobody will hack an illegal SP to be used on a few test systems. We all are waiting for the official release before using the SP on the main OS.