OS X 10.9: Deleting Keyboard Input Sources

This is really similar to: How to remove or disable a default keyboard layout? However, I am new here and have no ability to comment or make remarks towards this to voice further problems.

In OS X 10.9, I need to remove input sources in System Preferences > Language and Region > Keyboard Preferences > Input Source.

To be clear, I want these gone completely; if I were to click the add button then I want there to be nothing but the basic English layout available.

**Edit: The solution can be as dangerous as editing near-/root-level files in the OS as long as there's a possible solutions

If no possible solution can be found can anyone recommend third-party software or a way to lock system preferences?**

If others got here searching for how to disable all input sources except a custom keyboard layout, you can edit the com.apple.HIToolbox plist:

1. Change the current input source to your custom keyboard layout.
2. Open ~/Library/Preferences/com.apple.HIToolbox.plist (in 10.9) or ~/Library/Preferences/ByHost/com.apple.HIToolbox.*.plist (in 10.8 and earlier). You can convert the plist to XML with plutil -convert xml1.
3. Remove the input source or input sources you want to disable from the AppleEnabledInputSources dictionary. If there is an AppleDefaultAsciiInputSource key, remove it.
4. Restart.