More aggressive dictionary removal?

I'm looking for pointers on getting GHC to eliminate more overloading & polymorphism. I think this sort of thing mainly happens in the Specialise module. The default GHC flag settings get me a couple levels of monomorphization and dictionary removal, but I want to go further. I've tried -fspecialise-aggressively, but it didn't seem to make a difference, and I haven't found this flag described in the GHC user's guide. Anyone have pointers to more information? Thanks, - Conal