For the billionaire megayacht owner who still lacks that hi-tech submarine on his mega vessel, we have just the perfect one for you. Christened the Nautilus VAS, this private submarine from US-based Nautilus Submarines & Diving Systems is the only one of its kind. For its luxury-loving clientele, this private submarine offers the options of a lavatory, full-size stairs (versus a ladder), minibar, digital video, and music players, as well as standing room in its full-size submarines! All this comes for a price, of course. Yes, to own this luxurious toy, you will have to shell out a cool €2 million ($2.7million)! Furthermore, the VAS is the only private submarine offering a Diver Lockout option, which allows you to exit and re-enter the submersible while underwater. The submarine is also equipped with large flat, distortion-free optics that allows its passengers to have a crystal clear of the underwater world. The Mk III version carries five passengers and can do up to 6 knots. You are sure to be the envy of many a billionaire once you park this hi-tech luxurious submarine in your vessel.