I've been thinking about this issue as well, because I just bought an Abit IC-7 mobo and there is conjecture that these mobos may not be able to power the Intel Prescott processors when they come out.
The mobo has
Phillips PHB108 MOSFET's on it, which look to be state of the art. (I haven't found lower Rdson for a similar gate charge.) Perhaps by the time Prescotts have dropped into my price range, there will be better MOSFET's out there.
Short of better MOSFET's becoming available, I think the best solution is likely to be improving the cooling. I'd be inclined to just solder a strip of sheet copper to the tab of the MOSFET and stick it up into some airflow.
Brians256,
The reference design for the HIP6302 controller calls for using external gate driver IC's. Perhaps the gate drivers on your motherboard could be replaced with something beefier that would allow the use of MOSFET's with greater gate capacitance.
As far as the inductors are concerned, I'd guess they use Sendust/Kool-mu cores. It's fairly cheap and much better than powdered iron. I think the majority of the power dissipation in the inductors is likely to simply be the resistive losses in the copper wire. I wouldn't be surprised if the temperature of the inductors is mostly due to heat conducted from the MOSFET's. Rewinding the cores with heavier wire may be of some benefit, although you have to be careful that you don't increase the parasitic capacitance of the inductor. (You also have to ensure a beefed up inductor will still mount to the PCB acceptably.) I'd leave the inductors alone and focus on cooling/replacing the MOSFET's