Awesome. Heat doesn't "attract" dust either. I'm pretty sure TV screens get dusty because of the positive charge generated by the way the picture is created, which then attracts little tiny dust particles.
The only way I could see your heat theory working, would be to say that "dirty" moist air is brought in to the case, then the heat evaporates the water, leaving the contaminants as dust. Now that sounds plausible.
EDIT: Oh, btw. My tv screen gets dusty, but doesnt ever get hot...
Yes, but no sprinkles. For every sprinkle i find, i shall KILL you.