G'day jbuck,

Welcome to the Monastery.

Run the "Perl/Tk Widget Demonstration" (usually just referred to as the "WidgetDemo"):

$ widget &
[download]

Scroll down to the "Tix Widgets" section and click on:

"7. Multicolumn listbox with individual cell styles"

That seems to have the basic type of layout you're looking for. [It actually uses HList, not Listbox.]

The [ See Code ] button will show how that was built; however, it was probably written more than a decade ago. The current documentation is: Tk::HList.

See also Tk, which lists the current documentation for all the standard widgets.