Hi Andrew,
Regarding SVF file support for PSoC 3/PSoC 5, we have seen issues in doing programming with SVF file format. The reason is due to strict timing requirements we have to enter PSoC 3 Programming mode. A generic SVF file cannot be guaranteed to meet these timings. You can refer to http://www.cypress.com/?rID=44327 Programming specifications document (Step 1 in page.13 has details) for these timing requirements.
Regards,
Vivek