There is a driveline shop in San Diego, I thought in Clairemont. They did a custom shaft for my friend on his 87 Suburban. I thought it was South Bay Driveline? Call Oceanside transmission, they know of a really good shop too.
I would definatly recomend that you go to Oceanside Driveline, they are experienced with off road applications. They helped me out and others I know, while I have heard a few bad things about Vista Driveline.