[Overdriven]

I thought you were on the right track with the neutech setup, looks like a center diff in there too. If you're thinking about doing the rear diff from a 2wd 1/5 in the center, FG/Carson/Duratrax have a nice simple plate mount similar to a standard center setup I'd look into. The mounts are cheap, the FG diffs not so much, maybe the clones would be cheaper.

I hope the baja brakes work out for you. I think the rear knuckle looks like it would be easiest to mount to. And if you keep the solid center drive you'll still have 4 wheel braking, even with brakes only front or rear.