Hi there,
Your project got my attention and I would like to help.
I have around 6-7 years of experience with Xilinx tools and VHDL based development in general. I keep my knowledge up-to-date every day.
I have already helped a lot of people with similar request: writing the circuit logic in VHDL and testing it with a custom testbench so I think I can help you out!
If you are interested, feel free to PM me with the details.
Cheers, Andras