I would think it is more likely to see dust at f22 on any digital slr than not. It seems the sensor stain thing has everybody checking their cameras and surprised to find dust. The last used body I got back in nov. was really bad, and the blower didn't do squat. I tried some swabs that came 3 in a pack with some safe to ship fluid and they didn't work well either. I wound up using some lab grade methanol I had and wrapped the crappy swab with a lint free lab wipe (the kind you would clean a slide with) and it worked much better. I must have swabbed 6-10 times (new wipe each time) over a couple sessions using the blower after swabbing, until it was spotless. I figure a smoker probably owned it before me.
I checked my other cameras for the heck of it after that and they were dirty too, fact of life I guess.