Here is the answer - the Anker 40W 5V / 8A 5-Port Family-Sized Desktop Charger. One of these will definitely be going into my touring kit.
Just get a cheap and simple 4 to 8 port powered USB hub. From $5 and up on Ebay. Most come with a wall wart for 240v and the hubs themselves run off 5v or 12v. That's what I have sitting on the table near the front door. Everyone knows where their phone/ipod/tablet.. is and it only takes up one power point.