Michael in FtW: I'm not sure where you're coming from RE Microwaves.
The issue with the chicken isn't the bacteria content, but the toxins they produce as a byproduct of being around. Cooking kills off the bacteria but not the toxins, hence the problem.
Defrosting in the microwave is much quicker then defrosting in the fridge. Even though it may warm the food more then the fridge, it does so so quickly I think it would have less toxins then the fridge method, especially when you consider that microwaves are fairly destructive to organic lifeforms.
Feel free to correct me if I'm wrong, though.