Back in the early years of the 2005+ generation (e.g., 2005 - 2008) there was a lot of chatter about rear disk brakes and disk brake kits / big brake kits (BBKs). StopTech and URD offered kits, and some folks installed custom DIY setups.
There wasn't a lot of enthusiasm for installing rear disks, because a lot of folks questioned whether it was worth the effort - even on the X-Runners.
It was done, but I don't recall anyone who did it posting much in the way of details.