I would assume those 38.5's are Swampers whcih are really heavy, so a D60 front and rear or a D60/14 bolt would work good, but I agree, 13" is insane. I'm running 37's on my RE 5.5" kit. I would say go full width axles, because cutting down to stock width for your proposed setup would be dumb and dangerous (roll over easy due to high COG). If you don't want to do much fabbing, then about your best bet would be to buy axles already built for your application, such as Dynatrac, Tera, Currie, which are going to be big money. Ford Bronco axles (D44/9") just aren't wide enough for your setup, and they will still break, although not as often as stock axles, depending how you build them up (axle shafts, CTM's, spline count, bearing size, gears, locker, etc.)
13" of lift is going to require a lot of custom fabrication, not including the axles. Steering, driveline, suspension, etc. You won't just throw in coils, blocks, and leaves and call it good. The whole setup is going to have to be custom. I can tell you already, if you leave the leaf spring setup in the rear, the arch required to give that amount of lift, is not going to flex worth crap.
Anyways, those are my thoughts. Do as you will, but that is my recommendation on axles.