Prototype of the ACA2000 is a plain "copy" of the ACA500 with a different connector towards the computer. It works to a certain degree, but needs timing adjustments on the logic side - the exact ACA500 design does not work reliably in an A2000. I just don't have the time to continue work on that at the moment, because C64 Reloaded and the USB module are on highest priority right now.
Donutking: Yes, Chipmem access gets slower with an async A1200 accelerator connected. That's expected behaviour: It takes time to sync to the 7MHz Amiga, you always lose a statistical "half cycle", which gets a bit better with faster A1200 accelerators. In no case can you reach the full 3.5MB/second, so any game that *requires* each and every cycle will experience slowdowns.
ACA1230 memory issue: Although the ACA1230 is not covered in the "compatible accelerators" list, we'll take a look into the cause of memory disappearing. However, this has lower priority than the USB module and C64 reloaded, so no timeframe given here, and most of all: No promises. Compatibility with A1200 accelerators is only guaranteed with ACA1220 and ACA1232. Vesalia may give a guarantee for their ACA1231, but I don't.