fantagero, thats an interesting method you got there.

there are several problems of course. it would work, so long as there is a temperature difference, heat would be transfered [ie. cold air cools the right side of the HDD, the right side is cooler than the left, so heat from the left side moves right]. it would be terribly INefficient. there is too little surface area [as someone mentioned above]. if im not mistaken, the majority of the heat in a HDD is passed through the sides and not the top/bottom plates, so id assume fixing heatsinks to right side to work?

you thought of this to try to 'fix' the dust problem. unless you have a fully enclosed [or close to fully enclosed ] subsystem, the intake fan is bound to blow air all over the place. some of that airflow is bound to get further into your casing, carrying dust along with it. in an enclosed environment [ie. a tunnel], you'd only need one fan, either at the front or at the other end.

i really find the idea of a fully IN-OUT 'chamber' interesting! but at the end of the day, i think fan filters are just most practical!