I just got a Buddy Harness and my baby is just 1.6 lbs and fits here great. Here is the web site I got it at.
http://shop.muttropolis.com/product/...t-harness.html
Also if you are looking for a harness like the one on ebay Joy that is a member here makes some really cute one she is very talented. We have several members that make wonderful things for are babies.