I think that
this is what 71bronco might be talking about. It's called the "Bucket Grubber" on their website.
I talked the Brush Grubber folks on the phone awhile back about that product. They generally recommend it for a Bobcat/skidsteer rather than a tractor. The Bobcat can "twist" that thing around the trunk pretty easily while a tractor is going to take a lot more finesse.
On a related note - If you're looking for a hand tool to take out brush, check out the
Extractigator. I spent a ton of time researching what would be best for pulling honeysuckle around my place and settled on this. I found a website where a couple different people had owned similar devices from 3 different companies (weedwrench, brushgrubber, extractigator) and they agreed that the Extractigator was the way to go. I've been pretty happy with it.
OK, I'm done hijacking this thread.