DR has a 3pt one in their latest catalog for $1,699. There's a post that you can find by searching where they used the 3pt DR
chipper on a
BX2200.
I've an 8 hp TroyBilt Tomahawk that's into its 2nd rebuild of the hammers (and about 3 or 4 turnarounds: they have 4 edges). Works great but only does up to about an inch diameter. Loaned it to a friend recently who raved about it to work up some fallen branches from Isabel.
I've also a MacKissic shredder that runs off the PTO of my 12 hp Gravely. I only use it for leaves and small stuff because they neglected to put a
chipper blade on it. Also, it doesn't have castors; so it's a bear to go very far with it on the front of the Gravely. Wouldn't want to anyway without the
chipper blade, plus it's awful top heavy and could take the Gravely over with it.
The Troy Bilt is too top heavy, and the wheels aren't really road worthy to take it very far either by road or into the woods. You'd either tip it over (and it might take a small tractor with it) or run a wheel off it.
If your tractor isn't too large, I'd go for the DR 3pt and load the tractor with it on a trailer and take it wherever you want to go. I asked folks about taking the 3pt ones into the woods, whether top heavy, etc. Think the general feedback is they're a lot safer to transport that the stand-alone units, unless you go to the really big ones with heavy trailer size wheels, etc. Think you're WAY bigger than 12 hp then, and getting expensive.
Ralph