Idea Summary
If you provide an Apex PWA and the connection to the database gets lost an special offline page will be displayed. Usually ist is just a static page saying that there is no connection. 
But it can be a functional page too, with data,  javascript, forms and using a local datastore. But you have to code it manually.
This is already included in 23.1

I would like to have such a page using the css of my application. This page should automatically use the Theme and layout of my Apex app and provide place for one simple report and one form region on one table that is stored in localStorage. 
The data in this table should be syncronized with localStorage at page load if online (loading changes made while being offline to the database and providing a fresh dataset for the next offline period)    

Use Case
Field support has a basic inventory and form page even if they happen to be out of range.
Data entry would be more robust, too.

Preferred Solution (Optional)
This page would be defined somewhere in the PWA settings. (i.e. page 888 is the offline page). Its css and javascript and html will be stored locally - just as it is already done with the static offline page. Navigation should be grayed out in the offline copy.

On this page there is one special on load process - synchronizing table data with local storage if online. And a second one that reads data from local storage (maybe as json into an item).
One simple report that displays the data and one form region that provides edit functions.
Items with dynamic lovs will be rendered as the offline copy of the page is created (or updated) and their options will be contained in the html.
On submit the data will be written to localStorage again.