After first posting only the standalone (and, annoyingly, multi-platform) version of Service Pack 2 for Windows Vista and Windows Server 2008 to MSDN and TechNet, it looks like Microsoft has finally posted integrated versions of the product. That is, you can now download ISOs for discs of fully integrated copies of Windows Vista with SP2 and Windows Server 2008 with SP2 from both MSDN and TechNet (you know, if you're a subscriber).

Thanks to Emmanuel P. for the tip!