Right now, no. The Account menu feature currently will only show the menu items in one level, even if some options are nested. The idea isn't to be a full blown 'menu module', but a quick way for a few user-specific links to be added to your site. A multi-level system has a lot more requirements on styling and functionality, and would be very difficult to implement properly in the drop-down in a way that would work on multiple templates.
I can see adding a multi-level menu system in the future, but we don't have any timeline on when, or if, that would be implemented.
I hope that helps explain a bit more, even if it's not what you were looking to hear.
Thanks,
Alex