Engadget:

Nintendo is apparently concerned that the Switch's Joy-Con controllers might not be flexible enough. The console maker recently applied for a US patent on Joy-Cons with hinges that would let the top half "bend" to provide a more ergonomic grip. This would work whether or not the controllers are attached -- side sections would let you slide them on to the Switch's rails.

Sounds cool to me - my hands tend to cramp up a bit in portable mode with extended playing, so I’d love something more malleable.