You might want to read the information on the L-1 visa.
http://www.usvisa.com/l-1_visa.htm
I do know quite a number of people who have become permanent residents in the US based upon conversion from L-1 status.
I also have a friend who came to the US on a temporary visa, then the company was unable to renew it. He ended up living in the US illegally for a number of years, until he got a Greeen Card in the lottery. Another very good friend, went to Canada on business and was refused re-admission to the US due to his visa status and had to move back to the UK. He ended up getting all his gear packed up and leaving permanently.
In anything related to your career and livelihood it is worth the time to educate yourself completely and ensure you know the full status before you start.