Any chance of adding airplay support to Sonar... ? I normally mix using my wharfdale desk monitors but it would be very cool to play my mix on my higher end audio system without having to rendor anything. I would bet this feature would be used by alot of people if they knew it was available.

No.

You could try Airfoil.
 
https://www.rogueamoeba.com/airfoil/
 

Sorry for reviving an old thread, found it trying to do the same thing. if this is still an issue for anyone, I can confirm it works for me using TuneBlade as the AirPlay sender from PC.