If QML is there, that means that most of Qt should be around. Then it depends on whether the kde framework libraries exist already -- they might take a bit of porting. dbus support can be hacked out, that's not a big issue if it doesn't exist. Otherwise it should be really plain sailing.
If there are weird things like shared library limitations (like on Android) or process size limitations, that could be a big barrier. We fixed those for Android, though.