Sure there are numerous commercial packs of adapters for phones and the like but they tend to be expensive and don't necessarily work with each other.
To get round this the author of this blog has designed his own standard, based on the cheap and easy to use Phono (RCA) plug and sockets.
It works by you chopping up your existing supply cables and attaching phono plugs to both ends. You can then reconnect them in various configurations using female to female adaptors.
The full story can be found over on the Bit Bang Theory site at http://thebitbangtheory.blogspot.pt/2013/03/lab-tip-for-power-connectors.html