This is just a question that came off of the top of my head, but does anyone know if there are more sounds built into the system besides the (0x450) click sound? I would assume that there are others that can be put into apps since there are a lot more than just one built into the iPhone.
There is a list posted to AudioServices - iPhone Development Wiki. I've not yet figured out if using this in the following way is grounds for rejection:
AudioServicesPlaySystemSound(1103);
Don't forget to include:
#import <AudioToolbox/AudioToolbox.h>