Well, the picture on page G-139 clears up one of my mysteries: the spacer is a solid ring, and not slotted (as the Eaglepedia picture above led me to believe).
AMC of Houston, I'm assuming that you've seen, maybe even handled, the elusive spacer. Do you remember if it has any kind of bevel, or is just a flat washer of the correct thickness? I would consider just guessing at the thickness and trying to find a washer that size... but it seems like the spacer would have to have some kind of curve or bevel to sit flat against the flange on the axle, and the chamfer on the inner bearing.
I would still like to hear from those who, like mudkicker715, seem to not have these spacers on their Eagles. Since the final load on the wheel bearings is done by torquing down the axle nut, I was afraid I could not do that properly with the spacer missing. But maybe it just pulls a little extra slack out of the CV joint until the axle flange contacts the wheel bearing?
Thanks for the responses so far, guys.
JB