My application requires a 131072 point FFT. It looks like the Xilinx FFT IP only supports up to 65536 points. Has anyone else dealt with larger FFTs? I've browsed OpenCores, but am looking for any first hand experience if anyone has any.
Depending on what chip you have, a 2^17-point FFT is probably pretty huge. I'm not at all surprised that they don't support it. If you really need it, you could perform two 2^16-point FFTs, followed by a single stage of DIT at the end (or a stage of DIF at the start). Expect slowish clock rates and tons of resource useage though.