Sweet. That looks like a really nice setup, and you've done an amazing amount of work. Having been through the SAME sort of clearing I know what that's like. Many a winter day were spent sweating.
I posted this in the ICF thread a few minutes ago- but here are the rocks that we have on our property. I could move them carefully with my excavator- many of them outweigh the tractor I'm considering. My excavator was rated to carry 6000 pounds (close to the machine) and carrying some of these rocks was a really delicate process.
edit: wrong picture