It's not completely uncommon to be offered 16 oz or 20 oz as options in the US. But I see it more at "fast casual" restaurants than bars or more upscale restaurants.

And of course, what an "ounce" means may vary. According to Wikipedia "An imperial fluid ounce is defined in British law as exactly 28.4130625 millilitres, while a US customary fluid ounce is exactly 29.5735295625 mL, and a US food labelling fluid ounce is 30 mL."