I also backed the Everdock project on Kickstarter for 2 of their Duo docks. Looks like a brilliantly simplistic design that offers you the flexibility to use whatever connection cables you need for your devices. In my case for an iPad 2, iPad Air and two iPhone 4's. Should work equally as well when I upgrade our iPhones early next year by simply changing the connector cables. We also use the
Sanctuary4 from BlueLounge as a centrally located charging hub for our devices. It works quite well, and it too allows us to use the required charging cable for each device. For example we also use it to charge our Garmin GPS.
We also own a bunch of charging docks with fixed built-in connectors for the iPad 2 and iPhone 4. Next year, when we replace our two iPhone 4's and remaining iPad 2, they will be useless to us, where the Sanctuary4 and two Everdock's should work just fine.