I've been thinking about doing the same thing only with a sleeve hitch. Great idea!

I just finished buiding mine, I used the deck carriage and some creative welding I works great. I didn't build for the sleeve hitch though I felt like it would jump around too much. So I set it up to use the factory frame holes on the cub. It's actually on the back of my Husky now so I had to fabricate a bracket to mount it to the flat angled wall. I'll post a couple pics for you to see soon. I think your drawing may work but won't pull up enough earth to make the rows wide/tall enough.