Are there any file-based static cache options for Craft CMS?
Someone has recently developed a standalone static HTML caching plugin for Craft CMS which does similar to what you're after:

HTML Cache plugin for Craft CMS

This Craft plugin will generate static HTML files for your website. No need for Reddis/Varnish setups anymore!


Improves the speed drastically: 300-1500MS to 2-50MS (depending on
server setup) if ubercache is enabled from the settings page 
Busts the cache automatically when an entry has been updated 
Cache duration time can be set; defaults to 3600 seconds (1 hour)
Active development and support through Craft's Slack


NOTE: This plugin is still in beta, so please test if this plugin works as expected on a development environment before pushing to a production site.