I have a Mediator (Z4) Towered Amiga. I am going to up my 4000 though. It has real Z3 slots, and I just got myself a CyberstormPPC. BlizzardPPC cards are nice, but the version with SCSI are more difficult to find.
No all I need to get is a nice A4000 casing and a mediator 4000. I need the tower version of the mediator though, as the desktop one does not have a video-slot.