Go look in your local classified ads for someone parting out a 1981-1987 half ton pickup. More than likely it will have 3.08's in it. Realistically no one wants these rear ends, except when theirs fails, so the cost isn't that much. I'd pay no more than $100 for an open differential 10 bolt (1/2 ton) axle, complete, in good shape.
As long as its from a truck, you can swap axles easily between a 2wd and 4wd axle assembly, so 2 or 4 wd doesn't really matter.
Dorian
My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
Why insist on counting when the ring gear has the tooth counts stamped in?