I know RC4WD made those wheels and tires... The 80 FJ shell is only a few years old, and made by a Japanese or Chinese company. They aren't hard to find through normal RC stores though, that particularly deal in the overseas stuff. If you want to build one, it can be done. I'd start with a SCX10.
I'm building an 80 hard body replica of my '93 and I think it will fit the TRX4 with some trimming. Here's a pic of it sitting in place without the Defender mounting posts removed. I think it can be done, however, I might just put the 80 body on an SCX10 II.
Here's the driver of the 80, and the new BFG's that will be used for the build!