Attached Link: Mini 640x480 USB Keychain Digital Camera

Greetings,

Here is another inexpensive ($7.49 +S&H) alternative ...

Would this fit the conditions of the challange?  It's fixed focus, no
exposure adjustment, no zoom, ... and, best of all, cheap. 

Mini 640x480 Keychain Digital Camera

Miniature digital camera
640x480 (VGA) or 320x240 (CIF) image resolution
300K CMOS sensor
4 MB SDRAM memory
Holds approxmately 26 VGA (640x480 resolution) pictures
     or 99 CIF (320x240 resolution) pictures
USB interface
Pop-up viewfinder
Powered by one (1) AAA battery (included)
Integrated keychain
1.5 x 2.25 x 0.5 inches (H x W x D)

Just a thought ...

BTW, a battery powered webcam such as the Logitech Clicksmart 310
might also be appropriate. 

--
Martin