Some early estimates suggested that accessible and sustainable corn residue supplies are adequate for a new biomass processing industry (Gallagher and Johnson; Gallagher, et al 2003a; Gallagher, et al 2003b). Revision is justified now because the agronomic and economic environment has changed. There is also interest in the location of low cost supplies, because construction of biomass processing facilities is underway. A critical review for suitable cost estimation assumptions and sustainability concepts should also be incorporated in the revised estimates, given subsequent discussion.