Ruger came out with integrally suppressed barrel for 10/22 Takedown rifle. Silent-SR ISB supposedly can be as quiet as 113.2 dB with standard velocity ammunition. Barrel length is 16.12"
http://ruger.com/micros/silent-sr-ISB/index.html
Price: $629
Guns.com has some photos of internals
http://www.guns.com/2017/04/29/ruger-delivers-silent-sr-integrally-suppressed-1022-barrel-photos/