Methods and compositions for producing hRNA, e.g., shRNA, expression modules for specific target nucleic acids are provided. In the subject methods, an initial nucleic acid, e.g., dsDNA, synthetic DNA, etc., corresponding to the target nucleic acid of interest is converted to an intermediate nucleic acid. The resultant intermediate nucleic acid, following an optional size modification step, is then converted to a linear dsDNA that includes at least one copy of the hRNA expression module of interest, or a precursor (i.e., pro-shRNA expression module) thereof, where in certain embodiments conversion may include amplification. Also provided are reagents, systems and kits for use in practicing the subject methods. The subject methods and compositions find use in a variety of different applications.