Use Case:

The security announcements use a standardized template for all posts with a standard set of fields. Presumably we could build a set of fields for this category and make the articles use those rather easily. However, this category also broadcasts a RSS feed and is used by Feedburner for email notifications.

Would it be practical/possible to use the custom field data in the standard com_content feed view to still build correct entries?

I know full well non-HTML output in Joomla is rather limited as a whole (lacking plugin hooks, layout use, etc.) so this may be opening a Pandora's Box.