Mercedes-Maybach has rolled out the must-have wheels for the paranoid plutocrat, with a new, fully-armored version of its lengthy Pullman limousine. The Mercedes-Maybach S 600 Pullman Guard takes the 6.5m long – that’s more than 21 feet – car and gives it the sort of toughness upgrade you’d expect to find in President Obama’s Beast. In fact, it means you …