I asked the people on the Evo FAQ website if keyboard controllers were legal and they responded
Although we support the usage of brook converters, keyboards are not allowed in tournament play at Evo. Sorry for the inconvenience.
If you have any other questions, please feel free to reply to this email.
Is their any way to make them legal, because I’ve seen https://www.youtube.com/watch?v=AA_1azw_x-c which shows someone playing at Evo 2017 with a keyboard or has their been a rule change that broadly bans all keyboards? If their has been a rule change, does anyone know a way to get a southpaw smash box or something similar?
Thanks for your time.