the extra deep frames remind me of someone from this site, up the Kapiti coast I think? who ran "jumbo brood boxes", and they worked well for him. They might have been 5/4 size?
The spacer at each end idea addresses some of the issues with getting frames out, but as
@tristan says they could still get fairly sticky sometimes.
It will be interesting to see how it goes once he puts bees in it. I can't see why this system won't work for him, looks like he's had fun experimenting and building, so no reason he won't be able to address any issues if they arise.
I like that he says it's only really relevant in environments with long and extremely cold winters - so no need to look at this approach in NZ as the problem he refers to doesn't really apply. Nothing wrong with having a go with this system in NZ either, I'm too lazy to do it though