something like this would be very nice :
http://www.petelepage.com/blog/2014/07/devlab/Your shelf might do the trick though.
Do you want to make automated tests or just to have devices lying around for your devs ?
If these devices will only be used for dev-testing, think about including chargers. Nothing is worse than having to wait half an hour that a device recharge in order to solve a critical bug.
If you want to create a functional test lab, keep in mind that it should be easy to access to the cables and to plug/unplug devices.