You could go to http://www.inventua.com - they have a shadow module which allow you to mirror different modules through different portals. While it is not the smoothest way to do this, it does work.
I also at times have used the banner module - in host method to display images and content snippets throughout child portals.
Eventually I got a module written / extended for me on
http://free.dnnskins.com - and it allows me to share content through the 60 or so child portals that reside on that build. If you click on the dropdown menu at the top of the page, it will take you the different child portals that are running on that build.
There is no single individual content on any of those pages - each are from a module that allows me to share content through the html editor and when the module is installed on the page, I can select the content I want displayed and upon update, it shows it. I can also add new content into the page and select whether it's for host or portal use from any location on any child portal.
It's not perfect, requires some love, but the love of money, I can't find the source code I paid for many years ago to get it updated.
Nina
Nina Meiers My Little Website
If it's on DNN, I fix, build, deploy, support,skin, host, design, consult, implement, integrate and done since 2003.
Who am I? Just a city chic, having a crack at organic berry farming.. and creating awesome websites.