what size do you recommend for 167cm?
going to build a bike for my girlfriend. She is currently riding a gravel bike with almost mtb-like geo (long TT, tall HT, short stem) so it's impossible to compare the fit

Going by height only is not recommended for proper bike sizing. At very least you want to measure inseam length as well. If you really want to get it right, you'd measure leg length in two parts (ankle to knee and knee to hip bone), torso length, shoulder width, and arm length. This would give you the most important contact points to the frame.

However, if this is all you can get, then by height only I'd say a 52 frame would be appropriate, which would be a S for velobuild.

I am guessing that the domestic market price is probably realistic for making and selling higher end frames right now. I doubt anyone is making a ton of money here, but they are all taking their piece.

The result might be that high end catalog frames like these don't make a ton of sense, and these brands might as well raise the price a couple hundred USD and do the full development, like the Seka Spear RDC which isnt that much cheaper than the European price for the Van Rysel RCR Pro frameset.

I've been riding this week with it, not as many miles as I had hoped but a little over 60mi so far. I haven't taken it off-road, but I took a few trips to a parking garage and rode about 30+ times up and down. LOTS of rapid shifting and so far it's held up great. I'll be taking it on a century ride in a couple of weeks, so hopefully I don't end up stranded in the middle of it. I haven't put it through any water yet, but I'll get a bit more rough and rowdy with it off the road once I am done with my century ride.

My source sent me this photo that Magene told him about the shifter disc + rim compatibility. But I honestly have no idea how it works.

According to the Chinese conversation in the cyclisthub video, the hole on top is for mechanical brake cable. The hydraulic brake hose goes to the traditional location below.

It's one single design that accepts both mechanical and hydraulic braking. Neat.

Well that is a great idea.
You just need to provide a way to connect a cable to the lever along the hydraulic cylinder.
So if you use hydraulic, you just use cylinder. O
f you use rim brake you actuate both the cable and cylinder at the same time, but cylinder does nothing.
I wonder how nobody thought of that before...