Has anyone heard of the beaverbutt?  it will provide a docking station in billeted aluminium with its own power connector for gps and pdas?  

Not me. It sounds like a solution to a problem that doesn't exist when anyone who needs that sort of equipment on a bike could simply add a 12v power outlet, if he didn't already have one, and continue  riding without interruption. If the device required voltage other than 12v, Radio Shack has an adjustable voltage adaptor to solve that problem.