I see a frame around the NAND chip, but I see components near it, so no room around it unlike the previous models which had space for 2 NAND chips, so where on the main board are you referring to?
You see components
under it, as you'd expect on a layered logic board crammed into a tight space. The iPad 4's logic board is virtually unchanged from the iPad 3. They're still using the same part numbers for the storage and in the same capacity. It's hard to find teardowns of the larger capacity models because most sites that do them only buy the cheapest versions of what they need.
Come on now. You can make this as complicated as you want to, but the fact remains that no one is shipping a 128GB mobile device yet because no one has enough suitable 512Gb modules to supply it.
Here's a 16GB (1x128) iPad 3:
And here's a 32GB (2x128) iPad 3:
16GB iPad 4 (1x128):
Note the reserved space on the underside for the second module's connector. The Hynix part used in the 16/32GB models is a low profile (4-die stack) H2DTD. The only higher 4-die stack capacity is the 256Gb (32GB) H2DQE. There is no 4-stack 512Gb module yet available to allow a single-module 64GB version or a dual-module 128GB version.
The design, engineering, and production yield concessions to accommodate four modules or to use thicker modules aren't being made by any manufacturer. NAND producers have been focusing their efforts on other issues recently, most importantly cost and reliability. Increasing capacity means increasing number of layers or reducing the die size, which as I've said, had stalled out until recently.
