Here is a snow pusher I built. It can tilt to match the angle of the ground.
Here is a link to my build thread http://www.tractorbynet.com/forums/build-yourself/270685-quick-attach-snow-pusher-build.html
This is my first build. I wanted to make a lightweight quick attach that didn't push the attachments out changing the geometry of the loader. I also want a snow pusher so I decided to make that first and get the quick attach working before cutting into the bucket. I will be building it mostly...
I took some more pictures, it was hard to get a good view with the tire in the way. Kubota went to a lot of trouble to brace the subframe to the upper transaxle. My guess is this is for side to side or twisting load that you get when setting the stabilizers and digging.
Here are some pictures of a kubota subframe on my b2710 that I took awhile ago. If you want I can take some better ones of how its bolted to the tractor