Land Pride makes some good quality box scrapers. I have their hd 7' retractable ripper model. i'd say a hd 6' retractable ripper would be in order for your model. if you make the investment, consider a hyd top link, invaluable for earth engagement attachments
btw once owned the MX5000. a great no nonsense machine a step above the sub compacts.
again, recommend retractable rippers & heavy duty in whatever blade you decide