There's no reason why specific Kabini SKUs that don't particularly push the perf/W envelope should be delayed, unless:
1) it's a marketing decision;
2) they have real power management with Turbo, unlike most current Kabini/Temash SKUs, as this probably requires much more testing/qualification.
Turbo would be much more useful in notebook so that would seem to only leave one choice, which imo, is the obvious reason for this "delay", which is actually a reschedule.
It might not be the interesting or apocalyptic reason that many people hoped for, but the reason for the "delay" is almost certainly that Kabini would cannibalise Richland if it were made available on desktop right now.