previewing changes to published pages

This is one of the few instances where it seems there is a decision built in to the MODx core logic that doesn’t accommodate my workflow needs. I have several users who are very keen on being able to preview their page updates (ideally on a full-blown version of the page, with template, css, etc.) before publishing to the server. MODx lets me preview an unpublished page, and so that works for *new* pages. But once pages have been published, the ability to preview changes before "republishing" is not there.

Has anyone else requested anything like this? Is there a handy plugin or something?

The only workaround I can think of would be to make a permanent "Preview" Resource and then before updating an existing document, just choose the same template and input the new content. If everything looks ok in the Preview Resource, then go ahead and make changes in the actual resource.

Is suppose it might be possible to create a "Preview Mode" component that automatically copied the resource and all of its content to a specified location (perhaps a preview context). The component would take the id of the resource as an argument and would have options like "Delete All Previews," "Delete Specified Preview" and "Make Preview Live" etc.