Doesn't the modifieddate change even when you check the "mark page as changed" box before publishing?

Yeah - just noticed it in settings pane.

I also noticed that there was a hack used in EPiServer CMS 6 R2 that moved this property to the content tab and set it as checked - that doesn't seem to work any longer.

This code snippet was added to the global.asax.

		void EditPanel_LoadedPage(EditPanel sender, LoadedPageEventArgs e)
		{
			// move "Mark Page as Changed" checkbox to "Content" tab in edit mode and set by default to true
			string pageChangedOnPublishPropertyName = "PageChangedOnPublish";

			if (PageContentTab != null)
			{
				e.Page.Property[pageChangedOnPublishPropertyName].Value = true;
				e.Page.Property[pageChangedOnPublishPropertyName].OwnerTab = PageContentTab.ID;
			}
		}