Sounds exactly what we do.  We still laugh that 12 years ago when we were in the design stages of our new dairy, the engineer told us we couldn't bed cows like this.  Really?  Gotta love experts.  The mattress provides a BOTTOM so cows can't dig very deep, and the cow is unable to lay in a hole, making it difficult to get up.  In our heifer facility, we purchased used mattresses, again to be dovered in sand, for $5 a piece.  I just told tthe guy we'd take all he had, and some looked like they had never been used.  This hybrid stall seems to offer a lot of good and very little bad.  I was certain we were not the only ones with the idea, as farmers are a creative lot.