SOURCE: Intel plans to deliberately limit Sandy Bridge overclocking | bit-tech.net
We already know that Sandybridge won't have native USB 3.0 and SATA 3.0, now this.... If i know intel, they will probably want to charge you $10000000000000000000000000000000000000 for the overclockable version.
Makes me glad i jumped on the 1366 warwagon.