trying to free up a stubborn left front axle nut. I have a long breaker and lots of weight on the end of it, but no luck. Just wanted to do a sanity check; it doesn't look like it, but by any chance do they use reverse threading on the left axle spline?

 

I'm 99.9% sure that it is still righty tighty and lefty loosey. It was probably torqued to around 150 ft lbs and may have some rust too. You might want to try an impact wrench and this:
http://www.kanolabs.com/

 

Also try hosing the b***h down with PB Blaster. That's what it is made for is lossening stuck bolts. The last thing you want to do is put too much pressure and strip the thread on the hub or break the bolt. I'd recommend picking up some PB Blaster from any auto parts store or WalMart and giving it a good spray down, let it sit spray it down again, let it sit for a minute then proceed to trying and loosen that stubborn bolt.

 

It is regular thread. Make sure that the wheel is on the ground so it doesn't turn while you are breaking it loose. Then get a really long f**cking bar and have someone help you in cranking it off. I had a nut that didn't want to come off just like that and I got a 8 foot bar and a big friend, well it gave....

Don't be afraid of it, put your back into it!

Torque specs are 180 ft. lbs. but it feels like there is like 300 when you are taking it off for the first time.