Thanks to westcoastdrumz for starting this poll! We've contacted the vendor on your behalf and they've made the Leopold 21-Key Numeric Mechanical Keypad available.
Leopold: MX Brown
Goldtouch: MX Brown
Topre: Topre
Flico: MX Blue
Adesso: MX Brown
Note about the Adesso: an Amazon review indicates that the slash key is in the wrong place, which is visible in the image here (above the 9 instead of the 8)
Be advised:
WARNING: The current batch of Leopold Tenkeypads do not output true Numberpad codes and is therefore not recommended for applications that require Numberpad code output. The keypad is still fully functional for numeric input and calculation.