Many analysts have tried to gauge the effect of Japan’s troubles on Apple’s (AAPL) supply-constrained iPad 2, but the report issued Thursday afternoon by iSuppli‘s Andrew Rassweiler is the most thorough we’ve seen. He identifies five key components:

• NAND flash memory from Toshiba Corp.
• DRAM (dynamic random access memory) from Elpida Memory Inc.
• An electronic compass from AKM Semiconductor
• The touch screen overlay glass likely from Asahi Glass Co.
• The system battery from Apple Japan Inc.

Apple can get NAND and DRAM from other sources, notably Samsung and Micron. The battery, compass and glass are not so easily replaced, says Rassweiler.

The batteries manufactured in Apple’s Japanese factories are unusually thin, the compass was selected to work closely with the iPad’s accelerometer and gyroscope, and the glass seems to use the new Dragontrail technology that only Asahi can supply.

Hon Hai (Foxconn), which assembles iPads for Apple in China, is reported to have plenty of parts in hand, which helped Hon Hai’s shares rebound more than 1% in the Taiwan stock exchange Friday. Longer-term, the rate at which Hon Hai can build — and Apple can deliver — iPads may depend on how long Japan’s aftershocks and logistical problems persist.

Piper Jaffray’s Gene Munster pointed out Wednesday that because Apple tends to buy its components in large pre-payment deals that guarantee supply and pricing, it is probably in a better position than any of its competitors to weather the storm.

Also on Fortune.com:

• The day Apple landed in Gauna
• Japan’s iPad 2 launch postponed
• Video: Walking the longest iPad 2 line

[Follow Philip Elmer-DeWitt on Twitter @philiped]