It's not an uncontroversial implementation, but Rob Conery's web storefront project has implemented repository via Linq to Sql in C#.

http://blog.wekeroad.com/

Source is available.

He's not quite doing strict DDD, but his TDD is generally sending him out in that direction. The one caveat is that he has multiple repositories with no aggregate roots, so it's far from a textbook example. Also, earlier implementations of the repository returned IQueryable, so there were no domain boundaries on the repository, which is the source of most of the noise made about his design.