Valve has released Steam controller drawings for printing. Now anyone can print the controller and modify it under a Creative Commons license. But to sell the result of the work, you still have to contact Valve.

From this
link in Dropbox, you can download files for modifying the Valve controller using Creo Express or Native Modeling and the necessary materials for printing the case on a 3D printer. If you have any suggestions for improvement, Valve asks to contact her by writing to SteamHardwareFeedback@valvesoftware.com.
Steam controller preorders
started in October 2015 , and sales began in October of that year. On Steam, the controller
sells for $ 50 dollars, but not for Russia.