Siamese system offers this (even v2.1), however: scsi transfer speeds are limited (IIRC) to around 10Mbs for the full bus, so any devices which are being accessed will slow down network transfer speeds - ethernet (fast anyway) should be around 100Mbs [with the caveat that the crappy lack of DMA from mediator means limited to remaining PCI bus transfers after everyting else (graphics, sound, USB) has been taken off the fast memory ---> mediator transfer speeds].
Furthermore you would need to find a scsi card on the PC side which can change its own SCSI unit number, as the Blizzard scsi device is fixed as unit (0 or 7 - can't remember), and to run the scsi network the two devices MUST have different unit numbers.
I was musing before whether the mini-PCI attachment on the BPPC could be implemented to allow DMA access for the mediator by designing a BPPC - mediator bridge, but since I have no idea how to go about this, and both mediator and PPC appear to use proprietory closed drivers it remains a pipe dream.
Hadn't thought about that for the SCSI mk 4 though....
