The issue at hand is not supply related, but rather compatibility concerns between different components of the chipset. In particular, the PCI Express x16 slot and certain unnamed GPUs. Intel has contacted motherboard manufacturers regarding the technical setback and has stated they will have the problem solved soon, but still requiring a 2-4 week delay in launch.
This also looks like a good opportunity for Intel and its partners to clear product inventory using the P35 chipset, which will just be a year old next May. Back in August, we tested nine different Intel P35-based motherboards and found them to be excellent all-around performers.