> And if the catchall 's' is unweildy, you can have 'sp' for PCI, 'si' for ISA, etc.
I believe that is not the idea. The idea is, as far as I understood, to match the *labels* on the outside of the server. So the slot marked as "1" on the outside of the server should have a "1" on its network interface name, indifferent as to whether it is a PCI slot, a PCI-X slot, a PCIE slot, an ExpressCard slot some crazy hardware designer decided to add to a server, or some even crazier stuff (SDIO perhaps?).
Putting it in another way, what is in the inside (the bus used) does not matter, it is what is on the outside (the onboard port numbered Y or the slot numbered Z) that matters.