According to popular Market Research site iSuppli the recent devestating earthquakes over in Japan could cause a shortage for iPad 2 parts. iSuppli also did a deep teardown of the iPad 2 and discovered that 5 components come from Japan:

The IHS iSuppli teardown analysis of the iPad 2 so far has been able to identify five parts sourced from Japanese suppliers: NAND flash from Toshiba Corp., dynamic random access memory (DRAM) made by Elpida Memory Inc., an electronic compass from AKM Semiconductor, the touch screen overlay glass likely from Asahi Glass Co. and the system battery from Apple Japan Inc. There potentially are other components from Japan in the iPad 2, however, the teardown analysis process cannot always identify all components’ countries of origin

iSuppli also confirmed that most of these parts can be sourced from other countries as well even though all of the supplier’s factories are safe from the disaster.

Source: iSuppli