I would like to have posts excerpts from a single category load into my sidebar. I would love to be able to use the <--read more--> within the posts to dictate the output in the sidebar. When the read more is clicked the entire post should load into the single.php format.

… and so began another exercise in creating a plugin. This gave me an idea for some code, the code grew into a plugin, but I still wanted to get a better understanding of widgets and user options and now we have the BNS Featured Category plugin, fully widget capable and designed for multiple unique instances. The long description of the plugin reads:

Plugin with multi-widget functionality that displays most recent posts from specific category or categories (set with user options). Also includes user options to display: Author and meta details; comment totals; post categories; post tags; and either full post or excerpt (or any combination).

I have submitted an application to the WordPress Extend Plugins team for SVN space and hope to see an approval soon. The code is complete and ready to be used as of this writing.