No, 4x4 will require a minimum of XP Pro to support dual 'sockets'. XP Home on the other hand already supports QuadCore, by the virtue that it already supports the Pentium 965EE. I highly doubt that M$ will change that, it cant give its 'Pro' product to home 'Enthusiasts' and still justify the higher price of XP Pro to commercial users.
You dont even 'need' SP2 on XP home to support multicore processors, it works even with the original (pre SP1) release, but SP2 includes some pretty major bug fixes, so I wouldnt suggest anyone running the original release of XP without patching up