I don't think that Apple would use the ULV chips. In my opinion, they are just a marketing gimmick.
All the Intel processors use different amounts of power depending on the speed they are running, and depending on how many cores are operating. The "TLD" number that some people think shows how power efficient a chip is just says what the maximum possible power consumption of the chip is, with all cores at the maximum possible speed.
You can reduce the TLD (maximum power use) by just limiting the clock speed of the chip. If a chip could run at 3 GHz, but you don't allow it to ever go beyond 1.5 GHz, then the maximum power usage will be dramatically lower. However, the chip is not one bit more power efficient: Running at 1.5 GHz it uses just as much power as the 3 GHz chip when it runs at 1.5 GHz.
I think that is what Intel is doing with the ULV chips. If you run a normal laptop chip at the same low speed as a ULV, I wouldn't expect it to use much more power. On the other hand, the ULV chip will be limited in how fast it can do tasks. If I have a very CPU intensive job, I'd rather have the battery empty after four hours with the job done, than a battery that still has some charge left after six hours, but the job isn't finished.
Summary: Apple has never used ULV chips, and I can't see a reason why they would start doing so with Haswell.