Bernard Wolfman (Harvard) has posted Patenting Tax Strategies, 86 Taxes 33 (March 2008), on SSRN. Here is the abstract:

The United States Patent and Trademark Office has undertaken a practice of granting patents on so-called "tax strategies," legal plans for avoiding taxes. The issuance of those patents has been severely criticized by many, including the Section of Taxation of the American Bar Association. Concerns over the effect that patents on tax shelter planning would have on the practice of tax law, and on the availability of legal positions to taxpayers generally, have stimulated efforts to prohibit their issuance and to invalidate those already granted. None of these efforts has yet succeeded, but several show promise.