Clayton S. Reynolds (Orrick, Herrington & Sutcliffe, New York) has published Patronage-Sourced Income: An Expanding Universe, 58 Tax Law. 479 (2005).  Here is the abstract:

For taxable cooperatives, the distinction between patronage and nonpatronage-sourced income is critical. Subsequent to the publication of Revenue Ruling 69-576, there has been a notable expansion of the types of income that have been determined to qualify as patronage-sourced (sometimes with the approval of the Service but, often, in the face of Service opposition). This Article summarizes developments in this area and argues that further expansion is appropriate, especially in connection with the characterization of interest income.