Don't know if any are diverse enough to be granted that designation.
However, some of Apple's subcontractors/vendors may have some stock you can invest in.
Agere Systems, Inc., Ambit Microsystems Corporation, ASUSTeK Corporation, ATI Technologies, nc., Broadcom Corporation, Freescale Semiconductor, Inc. (formerly the Semiconductor Products Segment of Motorola Inc.), Hitachi Global Storage Technologies, Hon Hai Precision Industry Co., Ltd., IBM Corporation, International Display Technology, Inventec Appliances Corporation, LG. Phillips Co., Ltd., Matsushita, Mitsubishi Electric Corporation, NVIDIA Corp., Portal Player, Inc., Quanta Computer, Inc., Samsung Electronics, Synaptics, Inc., and Toshiba Corporation
The problem with conglomerates is that any shining unit they have is usually dragged down by underperforming units, but they are usually more stable.
Great if they break some of their units into tracking stocks, usually deadly if they decide to break themselves up.
---
However, if you want to invest directly in an Apple subsidiary, I don't know think you can.