Fluidized-bed membrane reactors (FBMR) are examined from a scale-up and practical point of view. Mathematical modeling is utilized to explore potential configurations for commercial FBMR steam methane reforming (SMR) as well as to quantify the effects of key design parameters such as membrane capacity, distribution of membrane surface between the dense bed and dilute phase, permeate side pressure, and sweep gas flow. Key factors affecting the performance of a commercial FBMR are analyzed and qualitatively compared with corresponding factors in packed-bed membrane reactors. Issues which pose challenges to the commercial viability of this technology are identified. These include maintenance of bed mobility in the presence of gas withdrawal, providing sufficient membrane capacity, wear, and mechanical forces on vertical surfaces.