I git a case 3D-printed for my ACA500+/ACA1234 accelerator combo. I found it on Thingiverse. It still needs some tweaks but I think my A500 finally looks nice with the accelerator. :
Vesalia Online - ACA-1233
ACA1211 - icomp - de
Commodore Szerviz és Restaurátor - Amiga 500, 500+ ACA500Plus