@RobDinsmore: I assume you are commenting on Intel's trigate technology (monolithic 3D) but Intel has also done pioneering work on 3D stacked chips starting 2002! It is true the marketing folks get carried away with what is realistic with all these new technologies but I wouldn't lower that to the BS-level!
@daleste: I agree, it is a challenge to develop materials for joining substrates, providing thermal pathways matching the conductivities of Silicon but therein lies the problem. There aren't too many gap filling materials with particle sizes in the order of a few microns. There are some promises in some emerging nano-particle based adhesives that the printed electronics industry seems to be forging ahead with (3M has a good presence there).
Dr. MP Divakar