In previous work we have developed and prototyped a silicon compiler which translates a functional language (SAFL) into hardware. Here we present a SAFL-level program transformation which: (i) partitions a specification into hardware and software parts and (ii) generates a specialised architecture to execute the software part. The architecture consists of a number of interconnected heterogeneous processors. Our method allows a large design space to be explored by systematically transforming a single SAFL specification to investigate different points on the area-time spectrum.