I wonder if it is somehow possible to permanently save a standard setting for KDE's open/save dialogue either for a single application or in general. I find myself often switch over to the detailed view which is gone again when I open the dialogue the next time. There does not appear to be an option to fix those settings. Is it somehow hidden, is there the possibility to do it at least via a config file?

The global KFileDialog settings are stored in kdeglobals (which is stored at ~/.kde4/share/config). You might want to see if the appropriate settings are there.