Take the editor interface from the cloud product and provide it as an optional library for privately hosted charts. Therefore, we can allow our users to dynamically format a chart (according to what we want to allow) with hooks so that we can privately save their changes.

For example, I want to allow users to customize the series color, marker size, style, etc. I can build my own web interface to collect/store these settings, but it would be great if there was a canned one that I can just plug in and capture the changes.