Add "Tags" as a field to the OSC admin file [url removed, login to view] (attached) where products are entered/edited. Use comma (,) as an indicator between tags, ie tag1, tag2, tag3.
Create a Div to be inserted in the OSC columns (either left or right) which holds the Tag Cloud you will also create based on the Tags field from all active products in the database. Each Tag represented in the Tag Cloud should then take the user to [url removed, login to view] (attached with the [url removed, login to view] file which is in charge of showing the products, you'll see it as a require in the index file) listing all products with that chosen Tag. If the user is already on [url removed, login to view], use AJAX to refresh the products shown so that only products with the chosen Tag are displayed.
I've attached a completed Tagging OSC contribution that may help you get started, although it's very different from what I am looking for.
This project should be fairly easy if you know PHP and AJAX well.