At Apple's last financial results conference, Tim Cook said the shortage of HDDs due to flooding in Thailand was something that worried the company. Said and done: today, when customizing an iMac in the North American store with a 2TB HDD, delivery is no longer immediate and moves to between five and seven weeks. We did a test at the Apple Online Store in Brazil, and even worse here: between seven and ten weeks.
The funny thing is that, when customizing a Mac Pro by choosing the same 2TB HDD, the shipping estimate is between three and five working days, that is, within normality even if the user decides to customize the four bays with 2TB HDDs! Other storage variations (from HDD to SSD) remain normal.
We will keep an eye out to see if the scenario gets worse (or not).