This is looking very good. The detailing on the brush is superb. Try doing a version with some paint on the brush and floor as some of the other commenters suggested. Oh and how about doing a full blown icon in 512, 256, 128, 32 and 16 pixels?
Alrighty, I'll try again. But it's difficult since the paint on the hair goes from smooth and 'solid' at the floor to not so smooth at the paint brush hairs (my english isn't too good, not sure if you understand what I'm trying to say)