I doubt that alot of DD contractors have DD samplers. But you may wish to contact Dr. Allouche at UWO, he was just at the International No-Dig 2003 conference speaking about some of his horizontal soil sampler. He may know of a contractor or, has a contractor he has used in his field tests.
Deep directional drilling has been used for the investigations for the new alpine base tunnels in Europe. This was covered by a lecture at the Geol Soc of London (Glossop Lecture) last autumn by a professor in rock mechanics from Athens University (can't remember the name).