I learned this last year when the 7Plus came out. If you have an Apple store close by, check for stock everyday. I got my X last Friday but for the heck of it I've been checking the two stores in my area. This morning both stores have all but the 64 space gray. They have the other three. If I didn't have mine I would be making a run at lunch time!
We have an order for 2 256GB Space Gray an 2 Silver ordered around 1PM PDT on 10/27. We were given the same 12/13 delivery date and still have the 'processing' message.