For those interested, here is what I have learned about the box blades.
There are three companies that I have found that make the roll over box blades: Bush Hog, Gannon and Woods. From what I can tell, they are all similar with respect to how they function. The Woods has a corner support that makes it seem like the strongest of the two. However, one could say that the other ones are strong because they do not need the extra support. So.. I don't really know the answer.
Gannon is made by Gannon in LA california. Woods is made in Illinois. Woods sells alot more of the smaller box blades, and Gannon is focused on more industrial type equipment. The list prices for the Gannon are lower than those of the Woods. However, the shipping and surcharges to get them shipped out are high. So, if you live on the west coast, you are probably going to get a better buy on the Gannon. Mid states to east cost, look for the Woods to be the better buy.
What I like about the Woods is what I don't like about the Woods: the corner support. While the supports will provide apparent additional strength, it appears from the picture on the woods web site that the support would also cause wet dirt/mud to hand in the corners. Look at the pic below close and you can see them in the corners.
Woods
List price for the FD100 (Gannon 65") is $1400.00. List for the Woods 60" is $1999.00. But, remember the extra costs of shipping and surcharges.
There is another manufacture called Gill. As near as I can tell they do not make the roll over box blade, but do make box blades. I understand that Woods bought Gill as well.
Bush Hog also makes one, but from what I can tell from pictures, it appears lighter duty, and specs on weight is less.
Bush Hog
I have more info if anyone is really interested.
I have called my local folks and getting prices. Woods does seem to have deeper discounts than Gannon.
Specs on the Woods shows it to be more lbs.