Denis G. wrote:

(...)

This doesn't solve exactly what you're attempting to do, but there's
an Atlas Copco hydraulic post puller made for road crews:
http://www.crowderhydraulictools.com/post-puller.htm
It's pricey (although maybe you can rent one) and it doesn't solve
your problem of grabbing what you want to pull (big or little). Just
more food for thought.

That is similar in concept to the cart I welded
together for the same purpose, though I grant that
it probably works faster than my little hydraulic
cart!

Turns out that I very rarely need to pull a post
that is still firmly affixed to it's footing.
A vast majority of the time, the post has parted
company with it's footing and my job is to lift
the footing from it's hiding place below grade.

Thanks!

--Winston