CrossRoads:
dipmicro - 6,8,10 pins
6-pin 1-row 0.1” Long Pin Female Header for Arduino Shields - dipmicro electronics
8-pin 1-row 0.1” Long Pin Female Header for Arduino Shields - dipmicro electronics
10-pin 1-row 0.1” Long Pin Female Header - dipmicro electronics
Stackable Header Kit 20x 8-pin & 20x 6-pin 0.1 (Total 10 Arduino Shields) - dipmicro electronics 20 pieces each 6 & 8 pinI searched this weekend at mouser, I don't believe they carry them.
Digikey lists Samtec headers, but none in stock, long lead time, expensive.
Sparkfun also carries them as sets.
Those are long-pin stacking headers. The original poster wanted solder-in headers like the ones on the Arduino. Of course you could solder in the stacking headers and cut off the excess length but if you are manufacturing something for wave soldering that would add an extra manual step.