here's my setup, home made spacer ifs rotor,caliper,hub. You loose 1/4" of contact space on the rotor since it's smaller then the fj40 rotor but for what I could have only 1 fj40 rotor, I had the spacesr made, new rotors and new pads. So who care about 1/4", I have rear disk brake!!
Now thats the setup im familiar with. A local 4x shop here has these spacer kits for about $100. Using IFS rotors and calipers. Good kit!