If I had spent my practice career on a smaller
  gauge instrument, I would be hobbled on any house
  piano.

I somehow find it unlikely that you could go an entire career without ever having a few hours to practice on a larger keyboard. TFA cites some research saying that it takes about an hour to completely acclimate to even the smallest of the standardized sizes they propose. I could sort of believe that you'd have not spent as much time stretching and might not be quite as flexible, but at the same time, I could also see you having had fewer hand injuries and being more flexible.

edit: I read more of the linked site. I no longer particularly believe that practice could make you better at reaching larger spans. http://smallpianokeyboards.org/pain-injury-and-performance-q...