I would have thought Sharpei, it looks like the tongue is blue, but that underbite and the body shape does look bulldoggy! Also something about the base of the tail. You never really know, but I wouldn't be surprised if there is indeed English Bulldog in the woodpile.
I personally think he's pretty cute! Not a mix I'd personally want to handle though, I'd imagine he's a lot of dog. I can picture the energy of a GSD and the hard-headedness of a Bulldog. Add that to what PaddyD said! Hope he finds a good home!
What an interesting combination. I don't think I'd want to combine those particular breeds, although it could be very good if things fell together just right. I can't call him ugly, but I really do love the pure shepherd look much more.