The quest tracker builds itself top-down. I think only an addon that fully
replaces the tracker would be able to reverse that. Most (including mine), if not all, that I know of only modify the default quest tracker. However,
my addon allows you to set the height of the quest tracker as tall/short as you would like to fit your UI and screen placement - it then allows you to scroll with the mousewheel through everything in the tracker window instead of hiding what is out of view. Clicking the collapse/expand button when the tracker is located in the lower-left of your screen will also cause it to expand/collapse the direction you are looking for.