There was a business in Nanaimo B.C. that used to convert a lot of these various surplus tracked machines for the logging industry. S. Madill is/was a big name in logging machinery and finally went out of business a few years ago. The name has been resurrected but I think they build all new now. Log yarders, loaders, mobile spars and tank rock drills of some models used the tracks and finals from surplus armoured vehicles. Many are still in use, and rebuilt as already mentioned earlier in the post. There are some good pictures and a bit about that company here:
http://www.heavyequipmentforums.com/...-in-Nanaimo-BC
Another place to get lost for more than a few hours...
Jess