I did a guinea pig tractor once and they did an amazing job on the lawn. They were the healthiest guinea pigs I ever saw; their coats were super shiny. They worked fast so I could move the tractor every day and they could cover a pretty big area over time. The lawn did have a patchwork kind of look with grass in the tractor blocks of varying heights but I didn't mind; the grass was super healthy as well. The tractor had 2 levels, bottom was the grass, upper was a sleeping/weather protection space. All their needs were met by the grass (they got their water from it too) so they were very low maintenance and easy to take care of. I know people eat them but I never did; too many kids in the area who knew them all by name. But they reproduce very easily so would serve that purpose if that was desired. The tractor was super-easy to move; I'd bump it around a bit so they would all go into the upper level and then I could roll it around without any worry of squishing anyone. I live on a hill now so this system wouldn't work for me anymore but if I ever moved back to level ground, I would do it again in a second!
