What makes a revit file size big?

So I'm trying to think about this very large project (1 to 1.2 million sqft + roofs) I'm going to be working on. The massing if fairly straight forward. It's a lot of boxes put together, all right angles. I'm only concerned about the structural side. We aren't going to be modeling rebar or connections. We may model gusset plates for braces, thickened slab edges, pits and depressions..... those kind of things. ie it's not going to be a very complex from that stand point. What it will be is very complex from a detail, sheet and view side.
I still have a lot of unknowns but it's looking more and more like many packages that need to be produced from one model. In theory we may be looking like 22 or so packages that may or may not align vertically. ie the foundation packages may not align with the steel packages. So we have a plan on how to get our screening done. We won't be using phases, we'll be adding a project parameter to each element that ties it to a packages and then use a view filter to screen anything that isn't a part of that package. Each package will be a stand alone package so I'll have many duplicate details. Details will, in most cases, not be tied to the model. So we thought we create them with detail components and detail lines then make them a group. Place the group in each drafting view. Modify one, you modify them all.

So this is the crux of my question. What create a bigger files? I'll have 2 plan views (one for a foundation package and one for a steel package) for each of my foundation areas. And duplicate views for foundation details where steel shows up. So it's only going to be modeled once, but it may show up in multiple places. We could end up with 1000 sheets in this model.
We are just really worried about having to spit the model up down the road after everyone else (A, M, E, P....) already has views and such set up. I'm sure this would cause a lot of heart burn since anything they had tied to one of our girds or foundation wall would be defunct.
So is the file size based more on number of elements and how complex the geometry is? How much affect dose the number of views and sheets have? Am I insane for thinking I can do this all in one model? Steve Stafford assured me that is could be done :shock:. But I'm still having my doubts.

Current thinking is to march down this path of one model (since we don't know what common walls will be associated with which phase of construction) for a while until either the model seems to get to big or we actually know when and where things are going to go.

Any 2 cent advice would be great. Heck I'll even take 1cent advice. And I've got a beer for anyone with nickle advice.
Thanks in advance.