Regarding me lending you my Al - I live in Europe, so concidering the shipping cost and, especially, time it would take to get to you, we might actually be better off solving the Cardbus issue here, or perhaps you might even be able to find one faster locally.
Ah yeah, in that case I think the back-and-forth on this forum actually is better

@LarsG5 @vectrex I now have a patched ROM
(MacOSROM.albook-cb1.hqx.sit) for you to try booting, as well as a new v2.0 compatibility checker
(CardBusCompat.bin.sit) to help me diagnose if anything goes wrong. Here's the sequence I'd ask for:
1) Run the v2.0 compatibility checker app FIRST, on your "stock" ROM with a card inserted, to give us a baseline
2) Back-up your current Mac OS ROM somewhere safe
3) Boot from another volume and install the patched ROM, reboot
4) Run v2.0 compatibility checker again to generate a second log
5) Send me both logs
It should boot fine, but make sure you have a recovery plan just in case it doesn't and you need to swap it back out. Try out your CardBus cards once booted and see what happens. As a bonus, NEC-chipset USB cards should now operate at
USB 2.0 speeds; SCSI cards should hopefully do their thing as well (I assume your SCSI card is specifically the PowerDomain APD-1480 which would be a key test subject).
Good luck! I am optimistic that we have a solution here. Getting working confirmations from both of you would be huge. If it doesn't work, send me a copy of your current stock ROM and I'll investigate.