I haven't had the oppourtunity (yet) to take one of these apart but from the looks of it I would think that modifying this to run both fans off of a single channel might be difficult. I would think that replacing components might pose another problem as I would guess quite a few of these components are surface mounted and when you start changing out components you tend to damage the board (if you don't have surface mount soldering experience) and who knows if the new amperage you are drawing won't damage the traces on the board itself. I wish I had an answer for you of how to accomplish this but until I can find one of these to disect and do the mod myself I am weary of giving any information which might cause you to destroy your equipment.
Bad advice can be the harbinger of death for electronics....
