Greetings Snap-together! I got my metal tracks from a guy in Hong Kong named Kenny Chong. Don't if he's still in business. Did a search and came up with nothing. However, metal tracks and other metal parts for 1/16 and 1/15 scale tanks are available from Backyard armor.
http://www.backyardarmor.com
They aren't cheap (close to US $200 for a complete set), but they are absolutely perfect in every detail, even to the small, angled cleats, which, incidently, are not included in the tamiya plastic tracks. I compared mine to the pics I took of the full-size ones in the Bovington museum, and couldn't find anything to criticize. They come in white metal and require quite a bit of prep work to get a weathered look, but once completed, they look great!
Currently, I'm on the lookout for some substance that I can use to simulate compacted soil in the indentations. If anyone has any recommendations, let me know.