If you turn off the preview pane in the References tool window, you can still use the "Preview tool window" to preview references. Using them in combination like this might allow you to organize the references list and preview in the way that you want.
I will file a feature request for the alternate layout for a future release.
I generally dock References to the left of the editor underneath the Defs/Project/Symbols/Open tool windows, and have the preview turned off.