I'm thinking about using some of my steel in my pile at home to convert my $200 drag behind plugger/aerator to a three point mounted unit. I rarely use it now because I have to stop the tractor at the end of a 300 feet pull to raise it before turning to go back the other way. It may be too much work for my light duty unit, but I thought I'd post it here to see what others have done. I'll likely keep the wheels and just shorten the raise/lower arm so as not to interfere with the three point a-frame.
Here's a three point conversion of a drag behind harrow that an ag student used for a senior design project. The diagrams at the rear are useful for dimensions: http://digitalcommons.calpoly.edu/cg...context=braesp
I have a bunch of square steel tube, 3/8" plate, pipe, benders, welding equipment, etc. It would not be too difficult to fab up a small frame and a-frame for the plugger. I bought 150lbs of concrete to make removable blocks for the plugger, and that got me to thinking about just converting it to three point before I form the concrete.
This is the cheap 48" aerator: Products > 48" Plug Aerator