It appears increasingly likely that this decision was driven not by space considerations (after all, the iPad is much larger than the iPhone), but rather by AT&T’s business strategy. This way, they can charge customers twice for 3G wireless data: Once for the iPhone, and once for the iPad.http://www.wired.com/epicenter/2010/02/micro-sim-business/
This really makes one scratch the head. From another wired story:
That iPad owners will likely consider taking a razor to the plastic SIM cards inside their iPhones, just so they can use the same portable data plan they’re already paying for, should tell you everything you need to know about the wireless data industry.http://www.wired.com/epicenter/2010/01/ipad-mini-sim/
I guess I can see why Docomo is "studying the business model" of offering SIMs for unlocked devices.