If you wanted to store your plugins in a database you could just use a standard Dreamweaver Recordset filtered however you need and then use static plugin and bind the value to the recordset column.
I'd like to investigate the problem you are experiencing with nested plugins. I believe it should work... What part of the page fails to work? Do you have an example you can share publicly here? I'll look into it further and see if we can get it working properly.