$this->bbcode_second_pass_quote('Jack', 'S')ciencegirl has the nicest ideas!
Still, I suspect bicycles with attached generators would work better. That way we'd use the power of the long muscles in the slave's legs. Also, we could easily chain them to the bike frame.
Optimum stable output would be about 200W per slave. I need about 10KW to support everything, including air conditioning. So that implies 50 slaves. Assuming I wanted to keep the load at 80%, I'd need 62. With three shifts...that looks like close to 186 slaves.
We could stack them up like caged chickens.

and then there's the slaves that have to cook 200 meals every shift, and the ones that need to work the rice fields... it's a logistical nightmare. and i doubt you can find 186 people in any large american city that can pedal for 8 hours straight