07-07-12: BtselectI happen to own two 120mm Noctua fans already, which were formerly used to cool a Class A amp that I no longer own. So the idea of using fans has not failed to occur to me. As far as making mountains out of molehills...
I think you are making a mountain out of a mole hill, I would just get a fan or two, place one under the amp and or one on top of the amp sucking out. I recommend using the Noctua NF-P14FLX fan.
Using the fans to cool the amp is NOT sufficient to change the amp's bias significantly. I've tried it. The amp's thermal vents are both narrow and few. The lid must be either removed or replaced. If the lid is removed, the amp is exposed to a significant amount of RFI, because there are 3 switching mode power supplies within 3 feet.
I've taken extensive steps to reduce the effects of RFI in my system, which were discussed at length in another thread. Removing the lid permanently has the potential to undo many of my efforts on that front. Not to mention, the fans themselves produce a considerable amount of RFI, so the idea of sticking two additional RFI sources directly above and below the amp isn't that appealing to me. Hence my decision to fabricate a mesh lid, which allows for much greater circulation than the stock lid (and therefore higher bias setting), while still protecting the amp from RFI.
So I hope you can see that the situation is neither a mountain nor a molehill, but something between.
Bryon