I think I have found a clean solution for this problem:
At the moment I'm using the editor registered for opening "txt" files for opening any text file from DFR (because often there is no editor registered for opening "conf" files and so Windows would use Notepad also the user has registered some smarter editor for "txt" files). I could make a setup page in the category "External program" named "Text editor". On this page one could choose
[x] Use default editor for "txt" files for opening all kind of text files from DFR
[_] Use default editor for "conf", "ini" etc. files from registry
[_] Always use Notepad
[_] Use this custom editor: _______________
And:
[x] Automatically convert Unix style text files to DOS/Windows style files before opening them.
(If this option should be on or off by default, we can discuss.) I think offering this option for all text files instead of silently patching just the scummvm.ini is much better.
Some little status update: The things above are not yet implemented but playing ogg files is working now, option for filtering games by emulation type is also done. At the moment I'm working on some tools for improving the navigation through the VirtualHD file structure. (Wouldn't it be nice to have a file list of a directory of the VirtualHD structure and clicking an exe file would automatically open it in DOSBox, clicking a txt file would open it in an editor etc., the context menu of the exe file would have a "Make profile for this file" item and the context menu of a folder would have a "Open this folder in DOSBox" item ?)
At the moment I'm planing to release a feature incomplete alpha version in about two weeks. The things above should be done by then. Some first improvements to the ScummVM support should also be ready (save path and more game specifiy settings) but ScummVM zip support, a ScummVM template, system specific auto mounting of CDs etc. probabily won't make it in this first alpha version.