Join two separate models, or create an "UBER" model?

[robblob]

I have a situation where I have developed two separate models, but now I'm being asked to join the two together.  I had originally designed the model with both models together, but was told that they aren't used together all the time and should be treated as two models, which is why they are two separate models to begin with.  Anyway, now that I have them modeled separately (and I saved the original where they're modeled together), what is the best route to achieve the best results?  I know there is a way to pull multiple models into a new model, but I've never done that and don't know when/how to use it.  I would have to join the model multiple times in order to get the desired results, so I don't know if the model of models approach would work for this either.  I've provided options below for how I see it in my head, but any advice is appreciated.

A: Revisit the original consolidated model and define the joins there and publish one massive model
B: Create a model of the two models and define the relationships there (how do I do this correctly?)
C: Other

I've heard that there are "UBER" models out there where everything is defined in one model, but I'm not sure if this is the right way to do it or "it just works".  Suggestions?

[bdbits]

You know that you can publish multiple packages out of a single model, right? You may not have ever needed to split them in the first place, as far as the users were concerned they could have just seen what they needed in a separate package. Don't let the user community drive your back-end design decisions, just ensure you can deliver the end result they are looking for.

I do favor the One Model To Rule Them All approach, with multiple packages as needed. I think it makes creating an enterprise solution with conformed dimensions an easier proposition. As a result, I've not had to merge models myself, so hopefully someone who has will jump in.

[robblob]

You know that you can publish multiple packages out of a single model, right? You may not have ever needed to split them in the first place, as far as the users were concerned they could have just seen what they needed in a separate package. Don't let the user community drive your back-end design decisions, just ensure you can deliver the end result they are looking for.

Yes, I knew that, but viewed multiple packages as being defined as different filter criteria for pieces of a model rather than different sections of a model, if that makes sense.  I appreciate the input, but from the sound of it, either way it makes sense to create the "Uber" model.