Yes, it's on the list. The only option right now is to open the model in XML and reorder the ORMDiagram sections by hand. This isn't bad in the VS xml editor: just collapse the sections and move them. However, we do not want to use this as the solution because of the huge hits taken anytime the file is under source control. We would also like to maintain position and zoom for each diagram. Position is harder than it sounds (if you open the model in a VS instance with more space than you saved it in, then an upper-left position may be too far down the model and would need to be adjusted). Would you also be interested in remembering position/zoom, or is it overkill?
You can view multiple diagrams from the same model using the 'Window/New Window' command and the 'New Horizontal/Vertical Tab Group' commands (on the context menu for the document tab). This lest you easily duplicate shapes (just drag from one window to another, or from the Model Browser), but is obviously still not the same.