If you are short on flip flops, have you considered using the BRAMs?  You would need 11 primitives (there are 264 in the LX130T) to make a by 792 bit wide memory.  You can set the BRAM to 'write first' mode, which will echo the data to the output.  The clk-to-out for unpipelined BRAM is ~2.0ns...slower than FF. 
   Since the BRAMs are dual port, you can use both sides of the memory (with different locked addresses), you can get enough storage for 48 stages of a fully unrolled algorithm.   
   I've never tried this, but was just thinking of how to make use of all the unused BRAM laying around.  I usually run out of LUTs, but need to rethink if this is worthwhile with the DSP48 implementation.