Thanks for the replies! Yes, I have seen the good material on the Cornell site, as well as several other sites. One that has my attention is a project in Vermont that's even posted CAD drawings/plans to build your own PTO-driven turner.
Man, you are right about the commercially built units being pricey -- ouch! We are considering going after some grant money for the project but even using OPM (Other Peoples' Money) I still am hesitant to go after that kind of funding. Hence any input from anyone who's actually using one of these things.
More background -- Currently, we are producing enough compost for our own use. Last year, we bought a 10-wheel dump truck that I use to go around to several large horse boarding farms in the area and collect 5-10 yards of stall cleanings every trip. And I'm collecting most weekends. We have applied much of what we have learned from several of the sites (Cornell's among them) to developing our own optimal "recipe" over the last couple of years of learning how to do real composting on a large scale -- Carbon to Nitrogen to Moisture to Green manure to brown manure to aeration and anaerobic to aerobic processes ... and chatting it up with big time composters at the Mid-Atlantic Nursery Trade Show we attend every year. As well as working closely with our local extension agent and the guru at Univ of Md. We think we are closer to upping our game and going bigger time -- producing for sale and even going after organic certification. Part of our research now includes our equipment mix. I think to ease compaction, improve mixing and aeration, and add moisture during drought, a windrow turner is a better answer than our current use of the giant backhoe loader (which requires about as much space to maneuver as an Iowa-class battleship

)
I'll check out that farmtek system once their site comes back up

The way I have to build the windrows, I think I need to turn them to get the best mix -- A local tree company dumps wood chips here and between that and the non-homogeneous mixtures of the horse manure I collect, I have to mix it by turning it -- hence my interest in the windrow turners.
A few of our neighbor farms (Plain Community produce farmers) have expressed interest in compost I'm producing and my immediate neighbor is currently letting me use about an acre of a field that adjoins my property for the large-scale project (he gets the bulk of the finished project).
One of the other things I need to figure out is if my current chore tractor is going to be up to the task (MF 1533 with 26 hp at the PTO) or if I am going to have to upgrade to a tractor with more PTO HP.
Thanks for the insight and input!
John