Mapping between genotype and phenotype using a model of biological development has been widely touted as a technique for evolving solutions to large, complex problems [1-3]. Here we describe two testbed developmental systems for evolvable hardware problems, and compare each to a naive mapping system. We find that designing evolvable developmental systems is not a trivial problem, however early analysis of the evolved structures demonstrates the potential of the generative processes behind development. We also account for the differences between the results of the two systems, highlighting the importance of search space evolvability over size.