To make the side column larger or to add more columns may be possible but it would require a bit of custom coding. You would need to start out by adjusting the layout to accommodate the extra columns. Once you have done this you will need to define these new columns in the css.
Next you will need to adjust or make a copy of the intermediate.php menu file. You would essentially want to have this repeat it's existing functionality but do it with your new column. Along with this you would need to adjust the recordsets in here to limit the number of categories to show and use an offset for the second column.
