Sadly, Geeklog doesn't have what I believe
CMS Matrix[*1] calls
Product Management[*2] .
The closest thing is Media Gallery.
Cons:
Your categories would look like albums and your sub-categories like sub-albums. Although you could use its internal search engine as an alternative to browsing albums, keep in mind the whole thing has
pre-defined fields (meant for media files) and, say, price ranges isn't one of them (you can't find an item that costs $5 if it only says manually $1-$10 in an item's description's field).
I'm not sure if it shows top ten/viewed stuff outside of the general stats though.
Pros:
You can allow adding comments for each item.
Since it allows members to create their own (sub-)albums, they could submit their own products.