Not sure at what level you are working with this - as a developer or functional user - but there are a couple things to consider. Scott McCulloch's (ventrian.com) News Articles has a "launch article" setting which means that when an end user follows a link to the entire article, it opens in the portal's admin skin. Typically, admin skins have but one content pane, and thus this would achieve your purpose.

From more of a consumer/functional perspective, you might be able to make Mandeep's "Live Content" module with its div overlay do something close to what you are after.