Ok so I get this better now. Essentially every system as it is installed should generate a custom database of devices and names, so that when new ones are installed they are given new unique dev names. I guess unidentifiable devices could be handled as a special case and default to the old behavior with a reserved subset of dev names.
Taking this furthur, it would be unlikely for a system to generate an overly large udev ruleset, even over time, unless it was a bit unusual? As udev is pretty much userspace, this should be easier to implement than supplying general case solutions.
I'm a bit worried that I might have a network card die, replace it, and then find that it isn't eth0 any more - for reasons I can't possibly fathom at the time, it's eth1. udev and static assignments is pretty advanced stuff and should be abstracted away from people in general. Craig