Did you get your original drive shaft back? If you have deemed that the u-joints are serviceable, make your measurements on how much you need to shorten the front half and start calling welding shops. We have one locally that shortens drive shafts.
I understand the pain of paying normal prices for services you can't perform yourself, but sometimes you have to bite the bullet. When you drive your E3 every day, it has to be reliable and in good condition, used parts are good as long as they work. My recent E28 rear axle conversion cost me about $250 total, paying to have it done would have cost much more. The new rear axle was interfering with the exhaust system, but I can't bend 2-1/2" tubing, so I had to visit The Muffler Store and pay $150 to get my exhaust system fixed and a new muffler installed.