Any solution to dust buildup in NSK2400?

[eternizer]

I built my HTPC with NSK2400 and I love this case.
It has divided chambers and many holes to help cooling the system, but unfortunately that's not particularly helpful when it comes to dust.
Dust coming in everywhere and I suspect blocking all the holes with air filter won't be good for the system air flow.
I considered making it positive pressure system. I could easily change the case fan direction, but not sure what to do about PSU fan. Maybe just setting case fan's RPM higher than PSU one will do? But thanks to the divided chambers, I doubt it... And I would still need to attach air filters outside the case fan, which again will hamper the air flow making the fan spin faster... (I would hate to attach an obtrusive air filtering device outside the case fan.)
Does anyone have any good idea how to prevent dust from building up in this case? Other than the abvious (regular vaccum cleaning)?