You could go to Moser, Strange, Curry, or any of the custom axle builders out there. Any one of them can build an “Explorer” axle for your Ranger.
But you don’t need it. I’ve built close to 100 custom width axles in the time I worked in my buddy’s chassis shop. Pretty much everything got 9” style axle retainers or full floating D60 ends.
Stock vs stock a 31 spline Explorer 8.8 is stronger than your common run of the mill 9”. The 9” shines when it comes to aftermarket support. You can build an insanely strong custom housing 9” from a catalog…. But you don’t need it.
A 5.0 swap Ranger on anything 35s or smaller only needs an Explorer axle. Even if I was snapping axle flanges off wheeling the piss out of the truck, I’d just weld D60 full floaters on the ends and throw some custom shafts in it.