At GRCon 2014, there was a lot of interest in getting a polyphase channelizer into the FPGA for applications like OpenMHz (which was easy to get running at the con with the bladeRF since it uses gr-osmosdr

With that said, we're going to be thinking about a good way of exposing processed data back to libbladeRF. I think this is something worth giving some good foresight in order to yield a sane API, and thoughts, feedback, pull requests, etc. will be appreciated.
One thought was for user-specific data formats, we could add a BLADERF_FORMAT_RAW_DATA value to the bladerf_format enumeration. In this format, our "sample" would simply be one byte, and it'd be up to the API user to parse that data as they wish.
In doing this, you'll need to add a couple cases to some switch statements, such as here and here.
Also, for a first cut at this, it'd probably be easiest to ensure data from the FPGA is padded out to the 4096-byte DMA blocks (which is the size of 1024 SC16Q11 samples) so you don't have to touch some of the existing assert() and error checks, firmware, and GPIF configuration. In the long-run, I think we most certainly want to dive into these items, though.
Hope that helps!
Jon