petco has harnesses called lil pals that are the perfect size for tiny ones. Not a huge selection but they worked well with mine girls. As for clothing, I went to craft stores and bought sweaters in the doll/bear dept. they were for teddy bears and fit great. Here is a picture of Bella in a bear sweater for Halloween. She was still under 2lbs at this point.
http://img.photobucket.com/albums/v3...DSCN1168-1.jpg