Got cameras in your data centers? If not then do you need some? I found a company that has a wide range of different video cameras and DVRs - even some of that can be hidden in inconspicuous places.
Head over to Supercircuits and see what they have to offer. The company recently launched a new camera and DVR combo product that is only 2" x 2", runs at 30 frames per second, has motion detection capability, supports removable SD memory cards, and can be hardwired to a power supply or use a rechargeable lithium battery. The device costs between $250 and $350. Check their "Hidden and Covert Video Solutions" product section.
They also have some IP-based cameras and DVRs.