Dave - thanks for that link to H.A.M.B., looks like that should work.
What about shortened shackles? Someone mentioned that somewhere. Can you just redrill your stock shackle plates, and how low can you go before problems develop???
An easy way to get shortened shackles on the rear is to just replace them with a pair from the front. You could redrill them also, shortening them up to the point of interference to the bolt that holds them together.