Consider CLIC dual wheels: Clic Wheel Systems Ltd - Dual Wheels for ATVs and Off-Road Vehicles - Products - Off Roaders
You will make a better, quicker, tractor decision is you study tractors in terms of (bare tractor) WEIGHT rather than SIZE.
I had discussed in length with one of the tractor dealers in Anchorage and settled on a Kubota B3350 but then after reading about all the problems with the emissions etc. I got scared off as even the dealer admitted it was a nightmare. There is ZERO support in Kodiak so any dealer support would have me shelling out the expense of a plane ticket, parts, room and board for a tech to come down....
So I looked at the B2650 but not sure if it has enough balls to do what I need? A fully loaded B2650 with loader and backhoe is less than 5K pounds.