Managed to get hold of mine today by phoning the Apple store (Buchanan Street, Glasgow) just as it was opening. Like most folk on here I'd tried to reserve at 9pm every night with no luck, so popped into the store yesterday and had a chat with one of the sales guy's who pretty much admitted the reserve online option was useless and that it had crashed completely on the Saturday night with no one being able to to reserve any of Sunday's stock, so come Sunday midday the store manager decided to offer anyone coming in that day's stock as no one was able to reserve, I'd missed out by about an hour🙄
Anyway the guy I spoke to said to call the store first thing in the morning as they get stock in everyday of every model, now, when I called this morning the first thing they asked was did I have a reservation, when I told him no due to Apple's servers timing out and being advised by a store salesman to call instead, they eventually gave in and reserved the one I was after. Took a few calls back to confirm the model I wanted once they checked the new stock but got there in the end.
So, my advise would be to call early bells and don't expect to be offered one right away, be persistent and firm but not rude. 🙂