If you're going to store cones of thread, then they'll have to be sitting up, and will need a much deeper drawer than regular thread. And even that is up for discussion, since I've seen one with 1 inch wood screwed/glued to the sides so they could add a drawer on top of the bottom layer. That way they could have two layers of thread, three if it was deep enough. Of course, to get to the bottom layer you'd have to either remove both top layers, or if they only take up half the drawer then just shove them back and forth to see all that is in the bottom layer.
With wood it's easy to add this and that to it.