My choice of axles I went looking for was in order:
1) 1976-1977 Early Bronco
- no cutting, already has disk brakes
2) 1989-1979 Big Bronco
- needs cutting, but has disk brakes, HP D44
3) D44, 1972-1975 Early Bronco
- no cutting, but needs a disk brake swap - could cost more than #2.
4) D44 from anything else. (lots of work!)
I found a #2, which also include the radius arms, complete axle, trackbar mount, and radius arm brackets.
As for strength - the components aren't any stronger, but there are aftermarket parts to beef things up, and it's way easier to fix than the TTB front end (my gear guy will work on the d44 for 1/3 of the cost of the TTB front end)
Oh, and the parts are cheaper. Loosing the ABS rotors (for the big bronco rotors, which are beefier than explorers) isn't breaking my heart.. or wallet! I can do a complete brake job using brand new parts for about $125. (calipers, rotors, shoes, bearings). My Navajo it was closer to $250 (rotors are ~$90 EA!)