Ok wow. It's very interesting that I should come across this thread.
Just recently, I have noticed my rear diff leaking from the rear cover and pinion seal. Deciding to replace both, I went and bought all the necessary parts.
The pinion seal was an easy find.
Seeing, however, as how my diff's front cover is rusting to death, I've decided to replace the entire cover/seal in one shot.
I had to order it from Auto Zone and I JUST picked it up tonight.
For $20, I got a lightweight steel cover, magnet, and gasket... as a kit. (magnet not pictured)
I'll be putting this on hopefully this weekend.
I'll definitely let you guys know how it works out.
EDIT: LMAO! I've just realized how amusing this will look: A rust brown rear axle with a brand spanking new shiny diff cover... (donning redneck flame suit...)