Submitted by Dogwater:

I thought this might be helpful info. I've been doing a lot of research on this subject lately, trying to refine my Patrol plan. Since the Unimog plan would take too long right now, I've decided for iteration 1 to use Datz's as a general model and look for an old Bronco and use the engine, axles, etc... out of that, so a lot of this info is centered around my Bronco research.

Detailed Axle Information about many different axles.

Axle Guide
Contains almost every 4x4 vehicle available in North America and the axles upon which that vehicle rides.

Axle Identification Chart
Pic and general info on Dana, Ford, Corporate and others.

Ford 9" info including axle widths

Matt's speed, Tire size, and RPM finder
Given any 5 of the 6 fields, this DiffGear will compute the remaining one.

Matt's Gear Ratio finder
Enter the Differential, Transmission, and Transfer case gear ratios then click on compute.

Dana 44 width possibilities using stock length axle shafts:
(all measurements are wheel-mounting-surface to wheel-mounting-surface, AKA wms-wms)
67.5" wide, 31.5" spring perch centers- stock Chevy 6-lug
69" wide, 31.5" perches- stock Chevy 8-lug
68.75" wide, 31.5" perches- Ford 5-lug outers
65" wide, ~29" perches- long side cut down 2-3/8", use 70's Ford long side axle shaft
63.5" wide, 27.5" perchs- long side cut down 4", use 80's Wagoneer long side axle shaft
62" wide, 29" perches- long side cut 4", short side 1.5", use 80's Wagoneer long side, Dodge short side.

Stock Toyota front axle measurements for comparison:
55.5" wide, 29" spring perch centers, '79-85 Toyota trucks and 4runners
63.5" wide, (set up for coil springs) 90-97 FJ80 and FZJ80 Landcruisers
'86-95 IFS front end is about 58.5" wide
'93-98 T100 IFS front end is about 65" wide

Toyota Rear Axle Widths:
55" wide, '79-85 trucks/4runners
58.5" wide, '86-95 trucks/4runners
60" wide, '95.5-up Tacomas/4runners
66" wide, '93-98 T100 trucks