Shawn,
It is possible to add custom tags for use with RSS feeds, which is done by adding them in a custom namespace. That's a bit more advanced, but that's how a lot of news providers do it. Folks like Google, Weather providers and the like extend RSS by developing a custom namespace. The biggest problem with doing it is using the newest version of DNN's news module. The reason being that there is no allowance for using custom namespaces in the current version. That lack of support is most probably due to the effort to provide the feed aggregation features. In short, when a collection of feeds is setup for use in the module, there needs to be some refactoring of the incoming feed and it is rewritten to what I call a 'DNN RSSv2.0' feed. Each feed can be of a different format, RSS, Atom, or OPML. The problem is how to piece them all together and render them for syndication. The method being used in the News module takes these feeds, analyzes them for conformance to the feeds specifications, then, if possible takes the most basic common tags to re-write it into that DNN RSSv2.0 type feed, so it can all be rendered. Now, the actual re-write will include only the very basics of an RSS feed, and really resembles the RSSv0.91 feed spec more than RSSv2.0, you'll get title, description, pubDate, and link, but little else - if that. Unfortunately, any custom namespace tages in the original feed are tossed out for lack of support.
Early on, in my tests of the new version of the News module, I had some issues with this approach, and for some of my work, I actually, did not opt to upgrade to the new version, prefering to keep the ability to customize the rendering xsl available. I do not need the aggregation features of the new module, and really find it not helpful for most of the situations I encounter. I put forward a suggestion to offer a choice of using aggregation or not, but it is hard to go back without a lot of effort and time to do it.
So, I can appreciate the need to customize a newsfeed adding a custom namespace with unique tags, but the current newest version will not support it. It's a good topic, though and I'll provide some discussion of how to do it with the older news v3.x module on my blog, if you are interested.