Hydraulic Top Link
Photos and info provided by Paul W.
If you looked closely at the "chipper in action" photos, you would have noticed a few extra hydraulic lines and a hydraulic top link.   Paul W supplied me a couple of pictures and some additional detail, so some enterprising folks can assemble their own.

BTW, a hydraulic top link is great for any 3 pt implement that needs constant adjustment over changing terain.  A hydraulic side link is also popular for adjusting the tilt angle on the fly.  Great for rear blades and box blades.
 
Info from Paul W follows:

The hyd. toplink is a cats ass.   Would not be without it now.
The cyl is 2" X 8" (TSC )    Cut the end bracket off and welded the eye to the cyl. Had to grind a small amount off other end so it would fit into holder.


Hydraulics Info:

You use a 4 port value. (IN) (OUT) (A) (B)
The out from the fel goes to the in on the value
The out from the value goes to the diverter value
The A&B ports have quick disconnects which give you the wet lines.
I run the top link, wood splitter,snow blower chute and if I had a hyd. dump trailer I would also run it off this value.
Keep all your hoses 1/2 "
When I run the wood splitter which has its own value I tie the value lever back on the tractor.