I totally didn't think about that.Most who Titan swap run wheel spacers in the stock rear axle anyway. Could just as easily get spacers to adapt 6/4.5 to 6/5.5.
I've done more searching through the internets and when I used "Titan spindle swap" I got a lot of results. I guess I was using the wrong lingo. There are several people on The New X that have done the Titan spindle swap with their suspension swap. The Titan spindle, caliper, and rotor assembly just bolts up. No drama at all.
The reason I'm researching this is I'm doing the all-the-way Titan swap later this year. VK56, M205, suspension, brakes, the whole tamale. I actually found that I can buy a wrecked Titan through a local place cheaper than I can buy the pieces and parts. And then I'll have a bunch of Titan parts left over I can sell and recoup some cash.