I don't think you're going to find spacers that thick because they are not safe. You will need an adapter, which is still basically a spacer except it has its own set of wheel studs. You bolt the adapter to the hub and then the wheel goes on the adapter.
A regular spacer puts stress on the wheel studs because the wheel is sitting way out at the end of the stud rather than down at the base. The thicker the spacer, the more stress on the wheel stud, the easier it is to snap them right off. That's why spacers are only sold up to a certain thickness.
Wheel Adapters Spacers