Scott,
Very uimpressive. You have tackeled this problem in the absolute correct way! "The other ED" has hit it dead on.
There are other ways but a lot of work and possibly welding would be involved. Adjutable control arms, especially the uppers sounds like your answer to the "pinion angle" solution. "JEGS amd Summitt" both sell the adjustable upper arms too. Just some more choices-Engine level, tranny almost level, at the tail, and the pinion angle negative (down 3 to 3.5 degrees depending on HP, traction and how hard you get on it! ( The more it hooks up, the harder you drive, the amount of time you stay in it, all equals to the 3.5 degrees!)
DV