According to Steve Purcell, the creator of Sam & Max, Sam is an Irish Wolf Hound.
There have been two canceled games in the series. The first was an action game called Sam & Max Plunge Through Space. The game was being made for the Xbox, but was canceled before much about the game was revealed. The second game, simply known as Sam & Max: Freelance Police, made it fair into production (to the point it was even rated by the ESRB) before being canceled due to "current market place realities and underlying economic considerations." When Freelance Police was canceled, many of the employees left LucasArts to form Telltale Games so they could make episodic games.
Lucasarts originally planned to make a sequel to Sam & Max Hit the Road entitled "Freelance Police". The game would have introduced both Sam and Max to complete 3D gaming animation. Many of the developers wanted to make Freelance police as a series of episodes. Due to creative differences between the developers on the game Lucasarts scrapped the game completely. It also led for Steve Purcell's copyright contract on Sam and Max to expire. The cancellation of Freelance Police led to the creation of the company of Telltale Games, who would later bring back Sam and Max through episodic gaming as well as introducing a new method of storytelling in video games.