It wasn't my intention that either of you cover old ground but, rather, fill in a couple of blanks so there's no jumping to wrongful conclusions.

There's a lot of rocks being thrown at MSNZ on this thread and, as a consequence we've seen an assertion by Crunch that "they don't have to do anything".
There's no doubt fault on both parts but there's no getting away from the fact that the reason you're in this predicament is your own failure to heed the time limit for old homologations despite a significant notified lead time.
A certain level of 'ownership' of the problem might go some way to securing the co-operation needed for resolution. I see that you have taken some in your latest postings.

There's been a number of unfortunate and outrageous statements made by various people, not the least being the suggestion that cages built to the standard MSNZ Sched. A designs are weak and/or will fail. That is nonsense. Surely the vast majority (shall we say ... almost all) cages employed in race and rally cars in NZ will be built to those specs and are tested in real life situations week in week out and prove perfectly adequate.

There's also been suggestions that "any cage is better than no cage". This is also not true as a poorly designed and built structure could, in some circumstances, be more dangerous than no structure at all. Hence the need for design rules.

That all said, and despite the onus on compliance falling with the competitor, it does seem remarkable that such a wide reaching and seriously impacting rule change could be enacted without MSNZ reviewing pending applications, and contacting and alerting those members affected.

If Ray's story is correct and his cage documentation was sighted and approved, with clearance given to paint the cage, surely there was an 'open' file somewhere that could/should have been accessed and acted upon.
Equally, if approval was issued or implied (presumably in writing) in 2006, it should be a simple matter to issue a homologation retrospectively.

Dave's case may be a little more tricky however it is not difficult to understand how a car builder could be estranged from the sport during the build time and not 'in the loop' when changes are notified.
It wouldn't be too difficult to write a strong justification for a derogation to homologate cages in cars that were genuinely caught up in this rule change, either to be presented to the Exec. for consideration or as a remit to conference which is only a few weeks away.
Any submission would, as I stated earlier, need to be supported by an indication of the size of the issue.