I'm probably eligible for a golden shovel :P
Let me get straight to business. Using those photos posted previously I've managed to do a CAD model of that desired stock. It's not complete - it's missing the mounting solution (not sure if I'd go for solid or folding stock) and it doesn't have the dimensions of the original yet, because I just guessed them or made up to make it look well

Because this model is fairly complicated, I think it should be done as a molded part. Obviously not having money for it, I'm probably going to rapid-prototype it once I'm fully satisfied with my CAD model.
Anyway, enjoy and leave some feedback