Manley Stingray iTube. ONLY $3400!!!
In all seriousness, though, I have a
Polk Audio miDock Studio. It's discontinued now, but maybe you can find one still. I got TWO of them on woot.com on a twofer Tuesday for $99.
That said, it's pretty old, so it doesn't charge through USB--Firewire only, which is really weaksauce. It has a pass thru dock connector, to which I attach the AC adapter that came with my iPhone 4. It charges fine that way...