Have you considered having the trusted nodes assigned to their own difficulty target? Instead of always using diff 1, do regular difficulty retargets on the trusted chain based on how quickly each trusted block was solved after their previous normal block, over x amount of trusted blocks. This is even reverse-compatible with the current chain. Just start having clients enforce it in a later version.
No need to always reinvent the wheel...
I always wondered why it was diff 1 also, I also suspect that Coinhunter has the ability to GPU mine this chain also. A single 5830 or 5850 could provide excellent protection against a 51% attack but would be useless against a trusted node ddos.
Why the diff 1 Coinhunter?
Well Diff 1 makes sense to speed up the generation of the '51% attack safeguard'.
It would make WAY more sense if the blocks were worth nothing or 0.00000001
... but that would remove the scam reason for them existing.
i.e. they are a scam since the OBVIOUS way for them to NOT be a scam was not used.
Seriously, if they were not worth something then there would be no reason for anyone to specifically want them, thus they would truly be what CH pretends they are: a '51% attack safeguard' based on a closed controlled block-chain.
However, the fact that the blocks themselves are under the control of only a few and they are controlled by only one - well you might as well go use a frigging bank - you can trust a bank or the laws they must exist under WAY more than someone who created SC1.0 (yeah people don't change they just try to find better ways to do what they did before, SC1.0 was a scam plastered with lies and deceit - as is SC2.0 created by the same person for the same reason, he hasn't suddenly changed ...)