When I heard about this Ergodex customisable keyboard on a podcast I immediately thought it would have uses in Assistive Technology circles and yes, they do already have information on such application of the device.
As it happens, this device has been around a while but only for Windows computers. Just recently has it been available to work with the Mac.
The Ergodex comprises individual keys which are arranged in any manner you wish on a plate on a tablet form of device. Each key can be assigned to do whatever function required. The possibilities are endless allowing you to customise any keyboard/input layout.