Lock down Word & PowerPoint features

Does anyone know of a way to lock down (remove/hide/disable) Word & PowerPoint in Office 2007?

Simply put I want to disable the user from using some functionality in them (mostly formatting). Some ideas of ways to do it, which I just can’t seem to find solutions based on:

Word has a protect document option which locks some features away, but I need more and also for PowerPoint – i.e. this is on a document level.
Some sort of UI automation which disables buttons – i.e. an application which disables them remotely. I am happy with the fact that if the UI automation is not running they get past it.
Group policy or registry settings
Rights Management Server (not sure even if that's right - just popped into my head)

The solution found was to create a standard VSTO add-in, add a ribbon (XML) to it and then using the commands node to disable buttons. For a list of the idMso's see this download.

<?xml version="1.0" encoding="UTF-8"?>
<customUI xmlns="http://schemas.microsoft.com/office/2006/01/customui" onLoad="Ribbon_Load">
<commands>
    <command idMso="Bold" enabled="false"/>
    <command idMso="Font" enabled="false"/>
    <command idMso="FontSize" enabled="false"/>
    <command idMso="Italic" enabled="false"/>
    <command idMso="Underline" enabled="false"/>
    <command idMso="Shadow" enabled="false"/>
    <command idMso="Strikethrough" enabled="false"/>
    <command idMso="ChangeCaseGallery" enabled="false"/>
    <command idMso="CharacterSpacingGallery" enabled="false"/>
    <command idMso="FontColorPicker" enabled="false"/>
    <command idMso="FontColorMoreColorsDialogPowerPoint" enabled="false"/>
    <command idMso="FontDialogPowerPoint" enabled="false"/>
    <command idMso="GroupParagraph" enabled="false"/>
    <command idMso="BulletsGallery" enabled="false"/>
</commands>
<ribbon startFromScratch="false">
    <tabs>
        <tab idMso="TabAddIns">
            <group id="MyGroup"
                   label="My Group">
            </group>
        </tab>
    </tabs>
</ribbon>