Had a bit of interest so thought I'd post an update. Our seasons are opposite to the US, it's spring here. I took 7 sc hives into last winter. Between then and now 2 were overun with mites, the others went into early spring looking pretty good, better than average even. However since that time the treated hives have been treated and the sc not, and the sc hives all have mite loads and are starting to lag compared to the others although still been able to take 3 nucs off 2 of them, and 6 nucs off one of them, 12 nucs all up, which also has controlled swarming in them.
The goal is 30 sc nucs by seasons end.
The jury is still out far as I'm concerned, with mite loads building in all of them this may be the make or break season. However the plan is 30 sc nucs this season, which may provide enough bees ongoing, to re-stock deadouts, and thereby provide an ongoing method to keep bees treatment free.
It would be very innefficient though and certainly not a good way to make money. However I'll carry on the experiment and see what happens. If I get a total loss of everything at some point, I'll be out for good.
From reading Beesource, it does seem an increasing number of people are having success in the US with treatment free, even some commercials, and nearly all commercials are reducing the amounts of treatments they use.
Of course the Treatment Free forum types are claiming this is all thanks to them breeding survivor bees. The reality, in my opinion, would be the breeding program being carried out by the likes of the USDA bee lab in Baton Rouge, which is steadily releasing good numbers of varroa tolerant bees into the general bee population, via the likes of Glenn Apiaries and others. I believe once treatment free theorists luck out & get some of these bees, probably without realising it, they then let anything that will die, die, which means the line is maintained. Course, they think it's because of feral survivor genetics but personally I don't buy that.
That's where I'm up to, and my thinking on things so far. Others will beg to differ.