This plugin allows theme authors to create a post tempate as well as page template for the single post.
Get the Beauty of Your Webpages in Your Posts Too
The plugin is to let users choose template for any post of any type as you can choose for page.
Adding Template Options to a WordPress Custom Post Type
This is a forked version of dotsquares' WP Post Template plugin. It allows theme authors to create a post template as well as page template for t
This plugin allows you to choose different template for individual post.