[Haskell] new "primitive" instances of Data?

I'm in the process of trying to write generic binary serialization code using the "Scrap Your Boilerplate" method. One bump I've run into is that there are no instances of Data provided for the extended set of numeric types (the stuff in Data.Word, etc.) and it seems to be impossible to hand-write an instance that behaves similarly to the instances for other primitive types. Any ideas for ways around this?