I wound up ordering an axle off a place in South Carolina called Dexter Parts Online. It got built and shipped pretty quickly by Dexter, only about 2 weeks after ordering. In case it helps other
Burro owners I put the measurements below.
My old axle was an Alko and it's either a 0 or -10 degree, hard to tell. The new Dexter is 22.5 down and wound up with +2.5" lift.
The bracket-bracket is 61.5". The old hubface-hubface was 76", the new axle is 78". I got a 2" wider hubface to gain clearance to fit 205/75/15 over the old 185/80/13 wheels and
tires. The old axle had the
tires quite inset into the wheel well and the new axle looks just right.
The pics below are in chronological order, with before and after pics. Also I haven't purchased new wheels/tires yet so the pics are with the old set.