I like to inform you herewith, that I have created an Excel Template to manage Test Results for Cases and Steps offline.
It's a first draft version, but offers already the main features needed.
I would be pleased to contact some interested key users / administrators to try the solution out, and discuss possible improvements.
Thank you
Volker
PS: Keep in mind that pictures, part of tet cases, are not transferred to the Excel Sheet, it's technical just not possible. But if the text itself is enought, then the solution is quite good to use.