I think you pretty well answered your own question. "Heck, I know a lot of guys w/ Nissans (xterra & titans, etc) that have had the paint peel off their rear axle becase of high temps."

After having a brand new D60 installed in our Jeep with an ARB I noticed we were leaking a little oil out of the axle seals so checked the diff temp and found it much like yours, too hot to hold your hand on. The Wife and I waited around for 10 or 15 min for it to cool so we could go the last 5 or so miles to home. I got out an IR temp gun and found it around 115* to 120* so didn't worry about it too much after that.