I think that some of these are a little far fetched (Steve seems to prefer less cutting-edge technologies), but ever since GrandCentral I have had the suspicion that Apple wants to have a runtime-variable number of cores.  That would be most useful as a power saving technique, which is generally how we improve battery life without increasing weight.  So, not having seen runtime variable cores in an iPhone (yet), but knowing that the tablet will have to outperform the phone with similar battery life, I think that we will see a large number of low power (ARM instead of x86) cores soon.