Re: Mapping plan
would almost certainly have had a direct mapping from the public IPv4 addresses to a (tiny) subset of the IPv6 addresses. If that had been the case then IPv6 would have been in widespread use years ago.
This is also in reply to the first poster above...
One of the goals of IPv6 was to make things easier for the routing system. Basically, the address space is carved out hierarchically with a top-level address registrar feeding down through RIRs (regional IP? registries) and so on down to local resellers and eventually users. It is assumed that the mainly geographical hierarchy will match up more or less with the actual routing infrastructure at at least the higher levels. Ultimately, the aim is to shrink the routing tables down.
IPv4 is decidedly not based on a geographical hierarchy. If you try and graft IPv4 addresses into the IPv6 system, you end up with an explosion of routing table entries that need to be taken care of. So no matter how you try to devise an IPv4 to IPv6 transition mechanism, if it involves a 1:1 mapping of old to new addresses in any way, you effectively break routing (or at least negate IPv6's native advantage there), and thus pretty much break IPv6 for everyone.
At least that's what struck me when reading the article.