single.php – possible different templates & select in /wp-admin/post.php?

I’ve created a single.php template and set display conditions to all posts.

Is it possible to create multiple templates and then select the one you want to use from within the WordPress post editor?

eg. My template is OK for most posts, but for some I would like no sidebar. I realise I can manage this by include/exclude within the templates, however that’s quite a messy way of doing it once you have many excludes…would be great if could select a template within the WordPress editor.

Thanks