There was a program for OS 8/9 called, simply enough, Virtual Desktop. I really liked the model that that program used - there was only one virtual desktop, which was larger than the physical screen. So, like a small browser window showing a large web page, you scrolled around the desktop, moving your 'view' onto that part of the virtual space (there were scroll bars at the bottom and right of the actual screen; I think you could choose where they should be).
What I found especially good about that way of seeing virtual desktops was that you weren't limited to fixed desktop views - you could look at a spot halfway between desktops, and so on.
For the more 'classic' sort of operation, you could set clickable shortcuts to particular regions of the desktop space. To get the overview, there was a way to sort of zoom out and see the whole picture, and then you could drag windows around the space, move icons to different spots, and so on.