Claims sales seems like a good idea, but most already make a post on the forums, though I guess they could do that with a link to the sale section.
Perhaps you could add photos of the fossicking areas, the entrance (as they might all look a bit like generic bush and river).
Perhaps links to metal detector, sluice, pan, dredge reviews that compare several similar models eg in a price range and functionality.
Video guides on how to use each piece of equipment.
Perhaps some maps that show where gold/silver is found through out new zealand.
Some photos of coins, gold that nz paydirt umembers have found & year, to inspire new people.
A direct link to NZPAM claims map.
Not sure if this is what you want, just throwing some random ideas about.