QUOTE (MortVent @ Jul 2 2010, 12:32 PM)

several corporate towns (aka incorporated suburbs) do it, they have private police forces that enforce laws and ordances there (think a homeowner's association is bad... wait till the city cops are paid by them too)
Any town (and a lot of other organizations you might not expect) can create their own police department. There is a bunch of paperwork and there is typically state requirements and some federal requirements (depending on your plans) but at the end they are a formal police department and can go and hire certified or pay the state to train police officers. (Though in some states it's up to an individual to pay for their own training...)
However the police are working for a government body, not a company. For example, if Disneyland had decided to create it's own police department they could have created a town instead of being part of Anaheim. IIRC Disneyworld is legally allowed to create a police department under "Reedy Creek Improvement District", but has chosen not to. However Reedy Creek Improvement District is a formally created political entity (created by the Florida legislature) and has elections and such. There is just a limited number of people who live in the District and who are eligible to vote.
http://www.rcid.org/AboutUS_main.cfm