Many years ago I used a company called MileMeter. Similar concept, except all you did to renew every 6 months was take a picture of your odometer with any digital camera or smartphone and email the image to them. No OBD2 tracking device needed.
It was very cheap for me, because the pickup I was insuring was barely being driven, maybe 2500 miles a year, since I put all my major driving miles on other vehicles, such as the work truck (18 wheeler) and my Harleys. I remember paying around $35 every 6 months. Yep. THIRTY FIVE DOLLARS for 6 months. Full coverage. Crazy.
Eventually something happened, I think Allstate and some other companies complained, sued, and bought them out. Bummer.
Currently there is a similar plan for motorcycles called Voom, and I did a comparison with my current company (Geico) and found the Voom rates were actually higher than Geico, mainly because I get a multi-vehicle discount with Geico.
So it pays to comparison shop. I'd sure like to see more companies offer by-the-mile insurance rates.