I haven't read all the posts in the other thread, but I'd recommend the component approach.
Just break your model into components and then save each component out to its own file. Then you can work on the individual files, and update them back into main model later on. This also allows for alternative versions of specific elements since you can have multiple files for any component.
Then on top of this if smaller files are slow follow guidelines by others about having shadows off, not show textures, outliner closed, etc.