I’ve been on the hunt for a solution to produce the needed very coarse wood chips(chunks) from 4" and smaller diameter/width mill ends or trees/limbs. Here’s something that I have found is nearly impossible to find in the USA but seems commonplace in some European countries. Take a look at the following YouTube videos. This looks like something that could produce a lot of nicely sized fuel very quickly.
There is only one I have found available in the US. It’s not shown on their website rojekusa.com, but I called to get information about it, they said they have it for sale and would e-mail information when their computers are back up. I will post the info when I get it.
You don’t normally find videos of this type of chipper unless you search using foreign language. Here’s the words I used:
Stepkovac Czech for “Chipper”
Drtic Czech for “Straw”?
Rebaka Polish for “Chipper”
http://www.youtube.com/watch?feature=endscreen&v=QEzwdKSIyoU&NR=1 only usa model I can find
http://www.youtube.com/watch?v=XdZfT4Xq8i0 nice video showing mechanism