Ramshackle Games have released new 28mm Dunger mounts with metal riders.
From their announcement:
New in the shop today are some more Dungers riders. This time the Dungers have integral modelled legs for the riders, like our bikes. The set comes supplied with the metal upper bodies from the biker gang set. The figures come with a selection of equipment and spare arms. The set is £16 for 8 resin Dungers and 8 metal riders.
The Dungers can also be bought as a set with no riders, ready for you to add your own. These cost £3.50 for 6 resin models.