@Dgold - I don't use the visual editor either. In fact I abhor the thing.
@StrangeAttractor - I modded core files which is something I advise against for 2 reasons:
1. If you don't know what you're doing you can completely f**k your site
2. Your mod will vanish the next time you upgrade.
Having said that the file you're dealing with is located at
quicktags.js and at about Line 60 you'll see...
Somewhere below that add...
That will add the pullquote button to the toolbar.