Check with any of the truck insurance companies. I would start with OOIDA, Progressive, Northland, Lancer. Some won't write bobtail unless you are leased to a carrier. A friend of mine bought a truck and didn't do anything with it for quite a while. He found someone to write a limited policy, but I don't recall the name of the insurance company. OOIDA would be your best bet to find something. If they can't help you, they may be able to point you in the right direction. You may also check with your personal auto insurance company and see if they could cover you with a short term policy or rider to your auto insurance.