My thoughts of how to accomplish this (without knowing how to impliment it). 1:When the user presses upload button. Override the normal upload form. Hit a webscript that will check the direction and return true/false if we are in the 'Campaigns' folder. Use the boolean to display addition options. 2: If I can edit the upload button depending on which folder we are in, I can drop in a custom upload button that will hit a webscript presentation with my own upload form.
2. Override the toolbar.get.head.ftl to include a new custom javascript file with a javascript class that extends the Alfresco.DocListToolbar class and overrides the onFileUpload method. Make your overridden method launch your custom uploader if inside the Campaigns folder and if not reuse the original uploader launch code by calling the method you override simply by calling Alfresco.DocListToolbar.superclass.onFileUpload(this, e, p_obj)
3. Override the toolbar.get.html.ftl template and change the javascript class that is instantiated to become your new custom javascript class.