I'm assuming that your fit was for a road bike with drop bars? I'm not sure that a flat-bar fit would equate, and I've never personally seen someone with bigger than 46cm road bars.
Nitto makes a 45c-c, RaceFace and Salsa make a 46 c-c model. The WTB model isn't exactly a traditional drop bar. I feel like we're missing some piece of information as I was unable to find a 50 c-c road bar, even in the wholesale listings.