Why I don't believe D&D are actually testing a new ANYTHING:
1. USPCC has yet to work with a company to get new paper. The paper they use is the paper that the mills provide. You can't just walk into USPCC and "develop" a new stock. They have what they have, and anything available to D&D is available to every person working with them. If D&D found a ground breaking new stock, you would see more people using it already. Just look at the Magic finish, which was printed on USPCC decks before a single Ellusionist deck with it hit shelves, and you already had custom decks utilizing that finish when it was just announced.
2. If USPCC refused to work with David Blaine on developing new tech and materials for cards (which is why the Legends deck is outsourcing to other companies), why would they give a minute of their time to D&D, who don't have anywhere near the resources that DB has? USPCC chucked E and T11 out the window so they could opt out of working with any company, yet they team up with D&D?
3. 100% of the time in the past, when a company or person stated they're "teaming up with USPCC" it has been on the design-end. The design folks have nothing to do with the production department, or R&D. At least that's what my conversations with their design department has led me to believe, since some of them are more clueless about stocks/finishes than us folks on the forums.