SwitchBoard.app is one of Apple's internal utilities. It's a simple launcher of other developer utilities. It's usually located in /AppleInternal/Applications folder along the other internal applications. Currently, there is no SwitchBoard binary available for public.
SwitchBoard and diagnostic utilities are copied onto device during restore with special IPSW file which is seeded only to Apple official service centers.
Note that this is not "Switchboard", note the lowercase "b", which is basically an internal "App Store" for Apple employees only.