Make Your Own Badge.

At OfficerStore.com, you can buy police equipments, such as batons, handcuffs, tire spike systems, and even real-lookin' badges.

The Internet is a wonderful place for cops wanna-be and criminals posing as fake cops.

Make your own shield: http://www.officerstore.com/store/shields-intro.cfm (via Spacegrinder and Boing Boing)

Update 5/5/06: OfficerStore wrote that to actually buy the badge that infer any police or security power, you need to provide identification.

The Build It See It Buy It program allows for plenty of creativity as we can plainly see in that image, however we most certainly will not allow badges like that to go through. In addition I believe it is important to state that we require identification on all badges that infer any police or security power. The order may appear to be accepted with out it, but I promise that you'll never see the badge without providing identification.
Thanks for the link though,
OfficerStore.com Management