I thought I'd follow up to my VANOS post after figuring out what the problem was...
The code pointed to a mechanical problem on a camshaft "position input; mechanical". After chasing the problem for two months in my "spare" time, I took it to a shop where they discovered two of the camshaft journal caps were reversed. When they went to swap them, they found that they were torqued differently, which prompted them to check the rest of the caps on both cams. ALL of the caps were incorrectly torqued! After swapping the two caps and retorquing the rest the code went away. I had a nice talk with the machine shop that did the head work, and to their credit, they owned up to their mistake and said they'd help me out if I needed to replace anything that was damaged. Engine runs great and everything "looks" okay, so it just cost me a little money and a lot of time. I'm not very happy it happened, but I'm very happy that its solved and I can move on from that car.
A stupid mistake that I should've caught myself.