Quicksilver accessible script for disabling and enabling Time Machine?
Just realized I could copy it out of another script I use to detect displays.

Here they are:

Disable:

tell application "System Preferences" to activate
    tell application "System Events"
        tell process "System Preferences"
                click menu item "Time Machine" of menu "View" of menu bar 1
                tell button "OFF" of window 1 to click
        end tell
    end tell
tell application "System Preferences" to quit


Enable:

tell application "System Preferences" to activate
tell application "System Events"
        tell process "System Preferences"
                click menu item "Time Machine" of menu "View" of menu bar 1
                tell button "ON" of window 1 to click
        end tell
end tell
tell application "System Preferences" to quit


Hope that helps someone else. If there's a better solution, I'm all ears!