Windows Close Button Resizer is a freeware from door2windows that allows you to resize the width of the close button in Windows 7 & Vista.
How to use:
Just run the tool, set the width and click Change. To restore the default size, click Restore.
Apps from door2windows are truly free and DON'T include any offers to install 3rd-party apps/adware/toolbars/unwanted software and never will. The apps are portable and don't require installation.