Hi Pzrwest try these links first one look under Field of armour accessories they have Steel wheels, sprockets, idlers and track for the Tiger in 1/6 http://www.r-c-tanks.com/
and try this next link for the running gear for the Panzer 111 and other tanks in 1/6 http://www.panzerwerk.com/
theres also Battle ready armour which make complete resin and metal kits in 1/6 for around the $500-$600 price range http://www.battlereadyarmor.com/

Cheers Ian