Yachts are so 2006--enter the luxury sub

Sure, a multimillion-dollar yacht is OK, especially if it has multiple bars on board. But the true seagoing sybarite needs a luxury submarine.

That's why some very wealthy adventurers are apparently flocking to U.S. Submarines of Portland, Ore., a company that builds custom models "for the eccentric billionaires who want mysterious and secret subs," according to Luxurylaunches. It says there are 100 luxury subs now in the water with unidentified owners. (Does DHS know about this?)

The price of covert underwater travel is predictably high, ranging from $12 million to $80 million. But you can get a perfectly decent 10-passenger sub on the low end of the scale for just $15 million, though the gym may cost extra. We already sense a new Tom Clancy book in the making.