John, you've probably already thought about this but, in the "painted limb" pic it looks like there's a sound tree directly behind the leaner. I'd consider tying into the sound one behind, work my way into the leaner and rig the brush out using the sound tree as both my TIP and Rigging point. You've just got the one limb that's of any weight and the rest looks like light brush. Rig the weight back to the sound tree with a Fig 8 and another lowering line from the leaner. You could even drop the limbs in between the trees and into the yard with this method (read Meunter hitch to Fig 8 w/cow hitch termination).
I wouldn't worry too much about the stability if you're not rigging big wood off of it. Of course, you've got a better look at the root structure than we do, but usually I find leaners like that to be pretty sound.
One drawback is you've really got to mind your lanyard cause you'll take a big swing into the sounder behind. The other drawback is painfully obvious but if you think the leaner is stable enough with just a climber, then I don't think a crane is necessary.
Just my opinion,
BAB