They're cool. They're PTO driven. My friends and I were talking about how cool it would be to use one in a zombie movie. They could just drive it fast into a crowd of zombies and chip like ten at a time.
Doesn't look that practical. Think about all the leverage on the machines over time. Visibility would be horrible. Re-learning to drive for that situation looks like it would be much harder than trailering, or just having that whole thing on the rear end and watch the swing out around turns.
If I had the option, I'd want the swinging bit to be up front where I could see it vs hiding behind the chip box in the back.
I had thought about powering a regular chipper with an aux transmission(Essentially a PTO rated to take full engine power) with the truck's engine. That would save some money and offer a decent power source. Thre are design considerations, but still a nifty idea, if they made aux transmissions for my ZF6.
There are other ways to do it, haven't fully persued that line of thinking however.
they are used here in the netherlands for working on the side off the road. The signals on the back and in front a big PTO driven chipper and a hydraulik pick up unit to simple unload the container with chips.
Its a giant investment and not so easy in the urban area or on the drive....it's not so big over here ;-)