The problem with the homeowner's policy route is that it doesn't cover damage to the tractor from the use of it, like if you roll it over. If you crash it into your house and the house were to fall on it, the house would be covered for damage but the tractor wouldn't be. Bottom line, be careful if you're relying on your homeowners policy and understand what is and isn't covered.
I called around to several companies about inland marine policies but the best I found was a "personal articles" policy through State Farm. I could insure the full value of the tractor (roughly $40k) with a ZERO deductible for just under $500/yr. With a $500 deductible it dropped to about $375/yr. The personal articles policy is similar to "scheduling" items on a homeowners policy. You can put just about anything you want on the policy....jewelery, coin collections, guns, artwork....you name it and they will probably insure it. I plan on adding a couple of my more expensive implements to the policy when I get them too, a snowblower and a grapple. A very flexible type of policy.
This policy doesn't have a liability component though but if your current homeowner's will extend liability then it sounds like you don't need more. If you do need liability then you can cover liability and the tractor with an Inland Marine policy.
