It's apparently a bad idea to put all bindings in one module, so what do you think is the more elegant way?
I think Bob's idea could be good start for this discussion:
It's hard to come up with one-size-fits-all rules for this sort of thing, but one Module per package is certainly a good place to start. Putting a Module in each package means you can make your implementation classes package-private--your Module will be able to access them and create bindings to them, but your users will not be able to access them directly.