Task manager with multiple layers of subtasks with own dates

I guess this is kind of a niche request, because I can't find any task manager that is close to this. I like Wunderlist, but it only goes one level deep of subtasks, and doesn't let you assign a date for them. I like Priorities, but it also only lets you have one layer of subtasks.

Bonus points if it was some sort of desktop application, and bonus bonus points if the icon isn't green or blue

 

Also times, for all tasks and subtasks. I don't understand why this isn't a thing