Izumi,
I'm also interested to know how many organizations actually have issues about the multi-homing criteria at the moment. We haven't heard this is an issue in Japan from our members at the moment. David, perhaps you've heard about a few specific cases?
I think that the reason there haven't been many issues raised at this stage is that IPv6 has not had widespread deployment so far amongst general businesses or enterprises; my observation is that much of the industry discussion up until now has focused on IPv6 addressing of ISPs or by ISPs of consumers using dynamic addressing (e.g. prefix delegation).
But I believe that as more business-grade IPv6 products become available, then certain types of companies will be reluctant to adopt IPv6 if it involves either numbering from a particular ISP's addresses (therefore potentially committing them to that ISP for a very long period), or requiring them to pay for additional services to multihome when they haven't had to do so previously, simply in order to qualify for portable assignment space from APNIC.
Again, I am assuming that most businesses would be likely to use IPv6 services using prefix-delegation or other dynamic addressing, or be multihomed, or be small enough to reasonably undertake renumbering of a whole statically-assigned network if necessary; but I believe that some businesses will not be in any of those categories.
(Also please remember that we are now the *only* RIR remaining that still insists on multihoming for portable IPv6 assignments.)
Izumi/JPNIC
Many thanks for your question,David