I agree with the above. Taking it a bit farther ...
Until the 28W parts destined for the 13" MBP are available in the quantities needed by Apple, they cannot announce the new MBP. It's that simple. The timing of the MBP release has nothing to do with Mavericks, Thunderbolt 2, or anything else but the suitable Haswell chips.
The most "custom" a CPU that Intel might make for Apple would be increasing cache size, adding execution units to the GPU, changing one or more clock speeds, or some combination of the above. The idea that a "custom" CPU for Apple would have new circuitry is absurd. Definitely nothing "hocus pocus". It would only be a new layout, combining existing circuitry in a different way. If at all.