It is hard to imagine circumstances where one would want to power on a blade server without the chassis.
The connector at the back of the blade server is not just a power connector. This connector includes 16 14Gbps SerDes lanes for midplane connection that can run different network protocols or external PCI-Express connections, connection to the power backplane and lights-out management.
Physically this is a MOLEX 75360-0018.It has exactly 100 data pins. Some of them would be used for the 16 SerDes lanes mentioned above, additional pins would be used for power connection, yet most data pins are probably not used in your BL460. However the midplane is passive and has all 100 pins routed.
I have talked to HPC enthusiasts who were thinking of designing custom modules to fit into the C7000 chassis. Such a project could not be started without a detailed knowledge of the midplane and backplane topology. Yet this information is not widely available. If you really need it and have the necessary competences, you might contact HP for information.