I stewed over this exact thing for a few years actually. There really isn't aything all Toyota that'll get you what you're wanting--if you want to retain the stock park brake. In my quest, I came accross tons and tons and tons of talk about using stock LC discs and subaru or nissan or trooper calipers. Only info that seriously turned up was from a guy from down under (bjonroids) that had done it and had some awesome documentation on what he did. If you run a search in the Land Cruiser section over at pirate4x4.com, you'll find his write-up. I believe he used stock LC front discs and stock front LC calipers--so NO park brake on the axle. I've seen a bunch of other Aussies that have done it, but the thing is, the Aussies got vehicles down there that we didn't. Point in case: the Nissan Patrol that's already been mentioned. So that one is out the window. And I could never get it figured out and never had the resources to figure it out, which subaru had some calipers that pulled correctly and could be used.
So here's the options that seemed to be out there:
1. Be the ginneau pig. Spend some time researching subaru, nissan, etc, etc calipers until you find some that pull correctly. Put on the discs (really not that hard once you read bjonroids write-up, you'll see how you can do it quite easily) and then figure out a bracket design and specification that will accomidate your disc and caliper. Then figure out how to mount it to the axle housing (welding it straight on would obviously be easiest, but not everybody wants to do that).
2. TSM. Look them up. They supposedly make a disc brake conversion for the 60 series FF rear. Uses GM calipers. (Again, the draw-back of non-toyota,)
3. 80 series full float rear end with discs. All stock toyota parts. The issues with the 80 series rear are that it is obviously setup for a coil/link suspension, it's almost 5 inches wider than the 60 series axle, and that the diff is more centered than on a 60 series rear. I looked into this quite a bit and actually ended up going with it (and so have others on this board). I couldn't have been happier with it. No worries on the suspension--all you have to do there is chop off the coil/link mounts and weld on some perches. Then you have to make a few extra accomidations to get the front axle to be as wide as the rear, but it's not that bad. All you need is the Sky's axle widening kit and some IFS mini truck front hubs. Cost me $250 extra. Then you'll want to get some wheels that have more back spacing than stock or you're tires will be sticking out a lot. I went with stock 80 series wheels. Do a search on here and you'll find my info on it (along with info on others who have done it).
Mine's long gone (parted out the entire rig), but if I were to do it over again, i'd save myself the agony of dealing with a 60 series full-float and go straight to the 80 series rear.
Honestly though, every single option for getting disc brakes with integrated park brake under a 60 series with full float rear is a huge pain in the ass. Good luck!
-Ferg-
