No third-party manufacturers for now
It's often said that if you want something done right, do it yourself. In an interview with IGN, Valve's Greg Coomer confirmed that the new Steam controllers will (for the time being at least) be produced by Valve, rather than turned over to a third-party for manufacturing.
On one hand, this sounds positive for the consumer. Valve believes that handling the production themselves will allow the product to get to market faster and they would have complete control in making sure it achieves the quality standard they're setting out for. It also means that they're taking all the risk on the venture, which could prove problematic if the controller doesn't sell. With Coomer admitting that Valve is, "disadvantaged when it comes to cost," they could really take a bath on this.
The new Steam controller Valve has been showing off is interesting at the least. I want one out of curiosity alone. Still, it looks alien and the idea of haptic pads in lieu of analog sticks could take some time to catch on, assuming it ever does.