Some people that don't use tools, don't know that the right tool makes money, and you return home with more energy. The AT make a good tag axle with a mini for moving logs on the right terrain.
If tight spaces are not an issue, designing one for your market might be best. I am happy with mine. When I'm in more open spaces, I wish I had more width-capacity.
I use PVC as stake extensions. Useful, cheap, easy, light, won't damage the chipper if they somehow find their way in (that shouldn't be an issue, though).