2. 64GB capacity is a poor argument for delay.
Samsung's 64Gb toggle DDR 2.0 NAND flash memory hits production
...3 weeks ago. The flash memory used by the iPhone 4 is supplied by Samsung. Didn't Apple just recently enter into a deal with them for some unspecificed iPhone/iPad components? Having only recently gone into production, I would say that it's reasonable that they would not have been available for the production of a June iPhone release.