It's amazing to see how much has happened since I started this thread. We now have frames, rims and tires, which is far more progress than I expected.

Personally, I'm now hoping the next step will be a dedicated 32" carbon gravel frame. Not simply an XC frame with a rigid fork, but a frame designed from the ground up for drop bars and fast 45–50 mm tires.

I wonder if any of the Chinese manufacturers are already thinking about something like that. I'd definitely be interested.