I went on the tour of their factory in Everett WA. Amazing facility. The 787s come in one side in sections. I think the entire fuselage is about 6 sections that they basically glue together. The parts come in one side and the entire assembly moves continuously until its complete and roles out the other side ready for paint. They could probably store a few hundred 787s while the battery problem gets worked out. Not that it will take that long.
Imagine a room so big that a 787 looks small. The room for the 747 is even bigger.
I toured the 747 facility in Everett in 1974 — it was spectacular then, too. I remember the videos of the stress tests on the wings and the take-off tests with too much rotation causing the tail to drag for a long ways down the runway (they had affixed lumber to the bottom of the rear cone for the test).