you know i thought this very same thought as i sat my in my landy 110 buried up to the diffs in a peat bog, a twin wheel set up would spread the weight a lot better and give better traction, so while the gears were in motion i did a search on here and found nothing so had chat with a mate bout it over a few as you do , so the long and short of it was as i didn't want to modify the body in anyway, id have to source a pair of narrow wheels and tires for each side just on the rears so's i could even get down any lanes or even out the front gate for that matter, and a double ended wheel nut/bolt to bolt all on with, and wider arch's to boot, anyway morning followed and i said bollox to that it was far to much hassle so as luck would have it i stumbled across something similar to these 15inch modulars which will do the job the without fook arsing about. then buggered back to bed