Is any way to template page result when network is not available?
Maybe not exactly what you are looking for, but I use Wire Monkey:
GitHub: https://github.com/ryvan-js/wiremonkey
There is also http://github.hubspot.com/offline/docs/welcome/ which I have used some.
Under the hood is google chromium embeded framework, so gdgsoft probably can allow to make dedicated offline page. Or maybe better better idea would be create after rendering website hook wich can be rewrite by phpscript 
Yes, you are correct. Sorry for recommending Wire Monkey, was a stupid idea on my part.
We’ll check that. It’s now on the TODO list.