What direction did you take? 

Tan Tan FM639, still waiting for paint and delivery. IMO Velobuild is less of a gamble.

Price should remain important, although it is trending in the wrong direction...

In the last Nero's show, although they were a bit off on the historical timeline of Chinese frames, they presented what they call a "third wave": branded frames aiming to sell for half or less than traditional brands

Good point :-)
Looks like a good one, maybe the price could be lower, but still..numbers are good and quality as well (I have a 909 allready)

if you're considering the 168, then get the 268. The 168 is outdated in terms of carbon layup. The 268 is reportedly as stiff as the 177, but it's more recent and accepts wider tyres.
Assuming you can fit yourself on it, obviously. If you have very poor flexibility, like if you can't touch your toes, then you probably ought to buy an endurance frame.
As for long term longevity, i wouldn't ride a VB frame from 5y ago because composites tech used has come a very long way (now stiffer, lighter, better finished inside, cable integration, aero, discs, better ride qualities...). in 3y you'll probably want a new frame anyway. Even though modern carbon fibre frames are, in principle, immortal.

Ok so similar in ant sizes and completely different in most other sizes

I doubt little people like being referred to as ants, but i genuinely didn't know 42 was a bike frame size. Or 45, for that matter.
The tooling cost to have fifty different frame sizes for a single model must be huge, i guess the existence of such small sizes means they plan to target China first.