Here's what I use for capturing Agnus traces on my HP 16700s and 16900:

https://www.techtravels.org/2013/03/bug ... -on-agnus/

Awesome idea and the board looks sweet.

Will you be releasing the Verilog/VHDL rtl source?

Beyond a physical board, cycle-accurate replacement modules will help a variety of causes like other FPGA-based amiga reimplementations.

Thanks for your efforts!