Mine is the low tech, low cost design, but it works for it's intended purpose, and it had to be something I could slide mostly under the ATV and still fit in my 5 X 8 trailer, so it was "purpose built" for that.
Also, since my upstate NY property has been / will be logged, nothing exceeds 20" any way.
The trick to it working correctly are the pivoting angle irons that keep the log centered, w/o them it tips over around sharp turns. We lift the end of the log with a timber jack, and purposely the end of the log drags as my property has some steep hills and I don't need the log pushing me down faster.