I don't have that problem, but I'm addicted to the rollers too !
It gets so much dirt and such off of the roof. I vacume it too, but honestly, I think that the lint roller does a much better job.

 

The brush I was using was a $2 bench brush from Harbor Freight. The bristles are soft plastic, nothing fancy, but it works great. Straw bristles tend to kind of break up and leave stuff behind. For $2 I can afford to dedicate the brush to MINI top cleaning only. Some of the better car care websites have some nice camelhair brushes but they're too expensive for me.

 

I cleaned the roof with the 303 cleaner. I like it, it worked well and my wife even commented that the roof looked brand new! One MAJOR complaint- the stuff smells like a Port-A-Potty!