A common question I received from customers is that they would like to edit property values during authoring time similar to editing placeholder content.
I have previously provided a solution for this but this needs to do some coding for every property. A better solution would be to have a server control similar to the MCMS placeholder controls to do this.
After spending a several hours I just finished such a server control which will be available on GotDotNet in a few days.
Here is an article with a brief description on the details.