How much are the adapters? I don't really see prices on that site.
It might have actually been Adaptec PCI in an SGI XIO-PCI card cage, memory is failing me. Definitely some dark magic required on Irix and on the FC switch and storage target side.
So after my XIO FC board died, I added an Adaptec board to my O2K to get my RAID array back online (the whole company was out of work because of that failure).
However though the card appeared in "hinv", it didn't work... After I asked for help on the newsgroups (the system was out of maintenance...) Alexis sent me a private email with the necessary invocation of the kernel rebuild command, and it worked like a charm from there.