VentureCraft should most definitely be building the VERZA for V-Moda; you could say they're the ODM/OEM for the VERZA. I assume that V-Moda is entirely responsible for the dock and METALLO case. However, I'm sure V-Moda footed a bit of the financial risk in the development as well; I'm sure VentureCraft is happy to have them as a business partner --- V-Moda handles the industrial design, and VentureCraft sorts out the electronics. I think they understand that it's their best bet for getting their core products out onto the marketplace (we probing head-fiers make up such a tiny chunk) even if it means having V-Moda branded stuff.
Why the difference in spec for the Go-DAP-X and the VERZA? Well, in these type of partnerships, a company like VentureCraft will present V-Moda with a number of different board designs --- they'll say, "this one is better for x, that one lacks y functionality, and that one's the best, but it costs $$$$" --- so V-Moda and VentureCraft will sit down and discuss what's best for them to present as a product, features and price-wise, as well as how much it'll cost to go into production. As the retail face, V-Moda will usually be able to specify which parts go into what and where, and at what cost --- they can help VentureCraft get into contact with various parts suppliers and help negotiate unit costs. In many aspects, this counts as R&D and patent invention as well --- not merely the circuit board stuff. This is the way it works with all retail/OEM relationships, from Apple/Foxconn to anything else as well.
How many layers is the X's PCB and is the circuit design much different from the VERZA? Well, we don't know, and neither VentureCraft and V-Moda will divulge, nor are they legally obliged to do so anyways. We can just keep guessing. We're only privy to what they release to us as marketing information.