I would like to develop a black paper stock to print on so when I wanted to create all black cards you would never get the chipped edge look.
That is a great idea but it also sounds very expensive in terms of how much a retail customer would have to pay per deck. The black paper process would have to be done before the stock ever gets to USPCC. I suppose they would add a black color to the paper mix at the paper mill. If they can do it with construction paper, I don't see why not playing card stock. I would also assume because of low demand, USPCC is not going to keep much black paper stock in its inventory. When you consider the small percentage of custom decks to the millions of standards that are made by USPCC, black paper storage and reduction of white stock per shipping volume to add black stock would also add to the expense. You also have to consider the changes to colors when the ink is applied. Bright red might not look like bright red when printed on black paper.
I see where you're coming from on this. But imagine if USPC decided to make some "special edition" Rider Backs in black, with the regular colors of a Rider Back deck but with that slick-looking black stock? That could be an awesome idea, and I think they'd find it popular for poker sets and the like.
I'm not at liberty to discuss this in detail, but USPC actually makes a fair amount of profit on their Custom Department, enough to make a concept such as this feasible. You do raise a valid point about how this would involve changes at the paper mill and not at their factory, but if any company would have the pull to get it made, USPC would be that company.
The biggest trick about printing on a black stock is just that - it's black. Applying ordinary ink would not work very well. But if it was some kind of, oh, I dunno - a silk-screen type process? - that would apply something that adheres to the surface in a thin layer, thin enough that the layer of laminate applied after printing would smooth out the surface and keep the applied ink from scraping off the card or interfering with the cards' movement against each other and hard surfaces. Or - and this would be an interesting concept - make the applied ink thick enough to actually be three-dimensional, something you can feel. It would be the first deck readable by a blind man that wasn't printed in Braille.