Haha, thanks
What you can do is add a right border to the DIV that all the main body content is output into, this way you can get the border to stretch to the bottom of your body content.
In your template_css.css file at about line 1004 look for the below and add the CSS border as I have below, change the HEX color to suite your needs
#s5_maincontent_left {
border-right:1px solid #000000;
Regards,