YC company Taskforce (http://www.taskforceapp.com/ http://www.taskforceapp.com/) does something very similar, although not having used it, I can't speak to whet

YC company Taskforce (http://www.taskforceapp.com/ http://www.taskforceapp.com/) does something very similar, although not having used it, I can't speak to whether they're focused on mobile as Taskbox appears to be.