The breed is a small draft breed. His conformation is draft conformation which tends to have this exact back and coupling (it is the coupling that looks a bit odd). He is not truly goose rumped.
His back is actually very very short and his conformation is designed for pulling which is what a small draft horse does. He is a bit butt high.
I will say that his conformation is very similar to that of the Shire or Clydesdale (without the size). I like that he is not sickle hocked.. something you find in a lot of drafters.
I like him. If he does not work out, ship him here and I will let you know when I am through using him!!!