Here's an idea. A tax on any product or service which is covered under a patent. The tax would be placed in government trust. If a patent is successfully invalidated by later litigation, then the court could award the successful litigant all or some portion of the collected taxes.
When the patent expires, the collected taxes is transferred to the Patent Office.
The intention is to increase funding for patent deliberation up front, and to create incentive for awarding enforceable patents.