Order by

When setting up a posts list, there are lots of “order by” choices. But the one that is missing is to order by the “Order” variable on the page or post. This came up for me while trying to build a widget to show lessons inside an LMS, I still want them to show in the order I defined when inputing the system data. Likewise this would be true for forums etc… Even better would be an order option by that took parent/child relationships into account as well and kept the child with its parents. (Maybe it already does that?)