Hi Ben,
I got some Roval wheel kits (hubs, rims, spokes, etc.) from Baron Corpucz, now in Santa Barbara. I forget the name of his business, but the CR list will help with that, I'm sure. At the time, he had many boxes of these, but I don't know if he will sell just the parts.
How many spokes do you need? I got a couple of extras with my wheel kits.
My examination of the heads of Roval, Campagnolo Neutron and Wheelsmith direct pull spokes suggests that you almost assuredly need to get the correct spokes.
Good luck Earle Young Madison, Wisconsin Offering expert wheelbuilding services for classic and modern bicycles