If I run the AppleScript code that Mr. Cleveland gave me on the latest iMac model (where ioreg fails) with OS X Lion, it returns lines including 'iSight' as follows.
"USB:
USB High-Speed Bus:
Host Controller Location: Built-in USB
Host Controller Driver: AppleUSBEHCI
PCI Device ID: 0x1c2d
PCI Revision ID: 0x0005
PCI Vendor ID: 0x8086
Bus Number: 0xfa
FaceTime HD Camera (Built-in):
Product ID: 0x850b
Vendor ID: 0x05ac (Apple Inc.)
Version: 7.55
Serial Number: CCGB5401HADDJRLX
Speed: Up to 480 Mb/sec
Manufacturer: Apple Inc.
Location ID: 0xfa200000 / 3
Current Available (mA): 500
Current Required (mA): 500
Hub:
Product ID: 0x2514
Vendor ID: 0x0424 (SMSC)
Version: 0.03
Speed: Up to 480 Mb/sec
Location ID: 0xfa100000 / 2
Current Available (mA): 500
Current Required (mA): 2
Mass Storage Device:
Product ID: 0x1336
Vendor ID: 0x048d (Integrated Technology Express, Inc.)
Version: 1.00
Serial Number: 6
Speed: Up to 480 Mb/sec
Manufacturer: Generic
Location ID: 0xfa130000 / 5
Current Available (mA): 500
Current Required (mA): 100
BRCM2046 Hub:
Product ID: 0x4500
Vendor ID: 0x0a5c (Broadcom Corp.)
Version: 1.00
Speed: Up to 12 Mb/sec
Manufacturer: Apple Inc.
Location ID: 0xfa110000 / 4
Current Available (mA): 500
Current Required (mA): 0
Bluetooth USB Host Controller:
Product ID: 0x8215
Vendor ID: 0x05ac (Apple Inc.)
Version: 1.91
Serial Number: 040CCEE73A50
Speed: Up to 12 Mb/sec
Manufacturer: Apple Inc.
Location ID: 0xfa111000 / 8
Current Available (mA): 500
Current Required (mA): 0
USB High-Speed Bus:
Host Controller Location: Built-in USB
Host Controller Driver: AppleUSBEHCI
PCI Device ID: 0x1c26
PCI Revision ID: 0x0005
PCI Vendor ID: 0x8086
Bus Number: 0xfd
Hub:
Product ID: 0x2514
Vendor ID: 0x0424 (SMSC)
Version: 0.03
Speed: Up to 480 Mb/sec
Location ID: 0xfd100000 / 2
Current Available (mA): 500
Current Required (mA): 2
USB2.0 Hub:
Product ID: 0x0608
Vendor ID: 0x05e3 (Genesys Logic, Inc.)
Version: 77.63
Speed: Up to 480 Mb/sec
Location ID: 0xfd140000 / 5
Current Available (mA): 500
Current Required (mA): 100
USB Receiver:
Product ID: 0xc52b
Vendor ID: 0x046d (Logitech Inc.)
Version: 12.01
Speed: Up to 12 Mb/sec
Manufacturer: Logitech
Location ID: 0xfd144000 / 7
Current Available (mA): 500
Current Required (mA): 98
UB623X :
Product ID: 0x6230
Vendor ID: 0x0cf2 (ENE Technology Inc.)
Version: 1.00
Serial Number: 606569746801
Speed: Up to 480 Mb/sec
Manufacturer: ENE Flash
Location ID: 0xfd142000 / 6
Current Available (mA): 500
Current Required (mA): 498
Internal Memory Card Reader:
Capacity: 16.02 GB (16,021,192,704 bytes)
Removable Media: Yes
Detachable Drive: Yes
BSD Name: disk1
Product ID: 0x8403
Vendor ID: 0x05ac (Apple Inc.)
Version: 98.33
Serial Number: 9833
Speed: Up to 480 Mb/sec
Manufacturer: Apple
Location ID: 0xfd110000 / 4
Current Available (mA): 500
Current Required (mA): 500
Partition Map Type: MBR (Master Boot Record)
S.M.A.R.T. status: Not Supported
Volumes:
SDHC 16 GB:
Capacity: 16.02 GB (16,016,998,400 bytes)
Available: 11.74 GB (11,742,740,480 bytes)
Writable: Yes
File System: MS-DOS FAT32
BSD Name: disk1s1
Mount Point: /Volumes/SDHC 16 GB
Content: Windows_FAT_32
IR Receiver:
Product ID: 0x8242
Vendor ID: 0x05ac (Apple Inc.)
Version: 0.16
Speed: Up to 1.5 Mb/sec
Manufacturer: Apple Computer, Inc.
Location ID: 0xfd120000 / 3
Current Available (mA): 500
Current Required (mA): 100
"