How about adding something like this ?
What about the possibility of a roller skid addition? So far this is the only way I can see how you might be able to mount one. This would require 2 small holes on each side. (Warranty Issue Maybe???)
This design idea might actually work; but, might need an angled shoe in front of the roller bearing to help protect it from uneven ground. I got the Idea after watching this: https://www.youtube.com/watch?v=VG1giQ0heaY Best part is that you can adjust the height of the skid so you don't keep breaking them so fast and protecting the lower edges. Just a thought.
See if you have any design Ideas!