I would say a Maremma Sheepdog X, however they aren't as common in numbers as the great pyranese...
But definatly looks like a maremma sheepdog X to me - I've seen a few maremma's that customers at my store have, and as puppies they look very similar! Here's a picture of one (a purebred) - and they have a similar head shape and ear positioning as some of the retrievers (a lot bigger, but there are similarities) which could give the look of retriever X?
The maremma's tails don't curl over their backs, but they do have 'gay tails' which do have an upward curve to them.
http://dogbreedinfo.com/maremmasheepdog.htm
Just a stab in the dark
