Best and safest supply for 12 standard servos or more?
Several comments to help you on your way. 

1) For your design of the regulator setup using the five 7805's do not wire all the regulator outputs together. Regulators wired in parallel generally is not a good idea er they will likely share the load evenly. Instead drive a small number of the servo connectors from each individual regulator. 

2) For the 7805 regulators to work correctly you will need to to provide a minimum of at least 7 volts. Slightly more would be better.

3) The 1N4001 input diode that you show for driving the five regulators is not up too the job is passing 5A. That part is designed to pass a maximum of 1A. So use one diode per regulator.

4) When you separate the regulator outputs make sure to provide some capacitance on each regulator output.