[hansvm]

Rheostatic and friction brakes both basically convert kinetic energy into heat. Is there some fundamental reason why a resistor would be harder to cool appropriately (low thermal conductivity comes to mind, though I'm pretty sure there are high performance ceramics used for both brakes and resistors -- my heuristics aren't really good enough to make a good guess for this one)?

[bigbubba]

Well, friction brakes are cooled by the airflow in the wheel wells. Perhaps you could aircool the resistors in the same place. The friction brakes would probably still be there though; would there be space for both?