(Edit:) On the hardware side, I implemented the Zorro bus protocol in the FPGA (in Verilog) and hooked it up to a SDRAM controller/arbitrator and DVI/HDMI encoder. There is also a simple blitter in the code.
Maybe even emulation of a faster CPU in FPGA (a'la the Vampire for A600).. though, it'd probably use the CPU slot instead of Z2/Z3.
Also, is it possible to hijack the function of the OCS/ECS/AGA directly via the Zorro slots (proxying the native output gfx output, e.g. with games), or maybe it'd require some kind of hardware bridge between the gfx chipset and your card?
On that note, i think the A500 my parents got me back in the day were a oddity. I distinctly recall it having 1MB chip ram, suggesting it had the ECS inside. But it shipped with Workbench 1.x rather than 2.x.
I can't remember whether you did the 1MB chip config with a dip switch or by cutting a track on the motherboard - I think it may have been the latter, which is probably why I didn't do it.
RAM was mapped at 0x80000-0x100000 from chipset point of view. CPU saw same data at 0xc00000-0xc80000.
http://www.bigbookofamigahardware.com/bboah/product.aspx?id=...
You could even argue Doom killed Amiga as a gaming machine.
As a former Amiga user, I'm familiar with the Amiga's graphics co-processor(s). I actually forget now how many, I remember Copper and Blitter, but don't recall if those were chips, or functions on a single chip.
So, is this a sort of video adapter that converts the native Amiga video output to HDMI compatible signals, or is it full graphics card that brings Amiga graphics (32/64/4096 color, with acceleration) to modern output resolutions?