Selby,
I don't know if this symbol already exists in some character set or not. I
did not perform an exhaustive search.
You can create your own using an EQ field, overstrike switch and characters
spacing the technique is illustrated at the bottom of this web page:
http://gregmaxey.mvps.org/Banner_Text.htm
Once you create the symbol you can save it for reuse as either an AutoText
entry (select it, press ALT+F3, complete the displayed dialog) or an
AutoCorrect entry (select it, navigate to "AutoCorrect Options" (Tool menu
in Word2003), select the AutoCorrect tab, click the "Formatted Text" option
button, then fill in the replace field with your trigger text and press OK.
Now anytime you enter the trigger text it will be automatically changed to
your symbol.