Never saw such a thing. I used the Mantis tiller for some years as I could start it, use it, and pull it apart for maintenance in the spring. I don't really have any areas that require that much cultivation for now. If we are successful in getting 5 or 10 acres out in the valley then I will look at lightweight tillers again. I have been very painstakingly digging up section after section of my garden (late last fall) as the weeds got ahead of me for a while. I dug them up, turned the soil, then put down cardboard and playground wood chips on top of that. I will spread preen on top of the chips next spring. That should at least give me a fighting chance of staying ahead of the little beggars. Except for horsetail. That is soooooo invasive and nothing seems to kill it.
I am making notes on what you large gardeners use for various things and hope to have the room to employ some of your tips.