I think there is a list of vendors and major companies used in the Apple 10-k.
"The Company believes there are several component suppliers and manufacturing vendors whose loss to the Company could have a material adverse effect upon the Companys business and financial position. At this time, such vendors include Agere Systems, Inc., Ambit Microsystems Corporation, Amperex Technology Limited, ASUSTeK Corporation, ATI Technologies, Inc., Atheros Communications Inc., AU Optronics Corporation, Broadcom Corporation, Chi Mei Optoelectronics Corporation, Cypress Semiconductor Corporation, Hitachi Global Storage Technologies, Hon Hai Precision Industry Co., Ltd., Intel Corporation, Inventec Appliances Corporation, LG. Phillips Co., Ltd., Matsushita, NVIDIA Corp., PortalPlayer, Inc., Quanta Computer, Inc., Renesas Semiconductor Co. Ltd., Samsung Electronics, Sony Corporation, Synaptics, Inc., Texas Instruments, and Toshiba Corporation."
So Quanta, Asustek, Hon Hai at a quick glance.