I've been reading more about the 030 PDS in Designing Cards and Drivers, and it seems like for the SE/30, VIA2 has the pins available for IRQ's to be routed for slots C & D. But since the IIsi doesn't have a VIA2, and it is replaced by the Ram Based Video of the IIci, partially emulating the second VIA's registers, I'm not sure the pins even exist to be able to route IRQs for those slots. I'll leave that to you hardware guys.

I'm also wondering what the Function Code pins (FC0-FC2) do. The best description I can find is: "Three bit function code used to identify the address space of the current bus cycle". I'm wondering if the function code should be adjusted when swapping slots around like I was doing with the SuperMac card.