Ask HN: Has anyone tried 'converting' a real-time path tracer to use FPGA?

I have seen a few demos of real-time path tracing software running on GPUs. I know GPUs are fast, but I wonder if there is a way to do the same math on an ASICs or FPGA that could be even faster? The main issue with existing things seems to be being able to do enough iterations to get a clear picture.