I spotted this on a child and had to ask their mom about it. They bought theirs at http://www.littleridinghoods.com/hoods.htm. I LOVE the idea, because I'm paranoid and don't let my kids buckle into carseats with their coats on. With a poncho, since it doesn't have sleeves, you can buckle the child in under the poncho, and they can still keep it on and stay warm. But $80 was a little out of my range. So I crafted my own for my toddler (the picture shows my 4year-old wearing it - she was the only one available for a picture at the time). I spent $8. What a deal.
(picture on left from www.littleridinghoods.com)
Quick instructions: Cut 2 squares of material - the one for the inner lining should be about 4 inches bigger all around. I used 1/2 yard of material, but should have made it bigger. Cut 2 pieces of each material to be sewn together for a hood (check out a jacket, etc, for an idea on size and shape). Cuff inner hood around outer hood material. Sew hood to poncho. Cuff inner poncho material around the outer. Voila. It probably took about an hour. Intermediate sewing skills.