Do you know where in the code the priority is set? The if have dolphin, use dolphin for desktop items, else use konqueror for desktop items? I would like to patch that for archlinux builds. That way I could still provide dolphin, but have the desktop items open in konqueror.
As a test, I just removed dolphin from the system and the desktop item do open in konqueror now. That is the way I want it by default. I've grepped tdelibs and tdebase for dolphin, but turned up nothing but the dolphine machine hardware in the admin dirs.
I don't know the logic of the underlying code, but look in the installed d3lphin.desktop file. You'll find two keys: MimeType and InitialPreference. Experiment with commenting out one or both and see how that affects your usage. You might need to restart Trinity or delete your tdesycoca cache files. Probably the best experiment is with a temporary fresh profile. That way no profilerc changes will affect anything.
I don't believe a distro-specific patch should be necessary. We should patch the behavior for everybody. Dolphin should not override anything until the user explicity starts doing so in the file association configurations.
Which reminds me of a discussion we had a long time ago: which apps should be the defaults for opening different types of files. We never concluded that discussion or decided anything.
Darrell