CableJive has released the US$25.95 dockXtender (http://www.cablejive.com/products/dockXtender.html) for the iPhone, iPod and iPad. It’s a dock extender cable offers a 30-pin male-to-female extension and is available in two or six foot versions.
DockXtender passes all functionality through to your iPad, iPhone, or iPod. Anything your iPod can do when directly attached to your accessory, can also be done when connected with the dockXtender, according to the folks at Cablejive. And it purportedly works with all cases.