> The real issue with this situation is working as a contractor on a single project. At the point you're working for one client, full time, as a contractor...you're an employee.

I disagree. I currently work as a contractor for one company more or less fully time. Because I'm a contractor, not an employee, I get to choose my hardware and OS, my own hours, I can take vacation when I want and most importantly, the employer can't force me to work in office.

Contract renewal is coming up soon, my rate is going up, and if they don't agree to it I'll just leave (if anyone needs a senior Java dev, email in bio :)).

> If you've got no other clients, you have no ability to negotiate with the simple statement

You don't need to negotiate, you need to assert you wont do free work and then don't do it.