Sometimes just asking a question will present the answer. I've been "googling" for quite a while without any results. Now that I posted the above, the answer came from the following site: http://cyberborean.wordpress.com/200...ose-key-magic/
To quote: "In KDE, open “Keyboard layout” configuration panel (Control Center → Regional & Accessibility → Keyboard Layout) and select “Enable xkb options” checkbox on “Xkb options” tab. Then scroll the options list down to “Compose key position” section and select a checkbox for a key you want to use as a Compose."
This key can be used in combination with various options to enter ligatures and other extended latin letters with diacritic marks and probably much more than I'll never need. I wonder why it's so hidden. Anyway... I'm happy now!