You can find reports of Costco cards being accepted in this thread...

http://www.flyertalk.com/forum/check...-security.html

...in this thread...

http://www.flyertalk.com/forum/pract...o-card-ok.html

and in this post...

http://www.flyertalk.com/forum/19749913-post30.html

(there are more out there if you go to the Travel Security parent forum and use the search menu).

I don't believe that the Costco card will always be accepted. Folks post here about using it because they think it is absurd that they get away with using it, since it's not on the TSA's list, and it's not issued by any government. It also costs USD$ 55 per year, and is only good for one year, both of which are drawbacks.

Will your government issue you more than one passport? If they will, you could show your second, unmarked, boring passport to the TSA and keep the one with all the attractive stamps and seals and visas out of sight. For example, the U.S. will issue a second passport if (1) you have Israeli stamps in your passport and fear they will cause trouble if you travel to Arab countries, or (2) if you travel so frequently that you need to have one passport that spends most of its time being mailed to the embassies of obscure countries to obtain visas while you and your main passport are off seeing the globe.

http://www.state.gov/documents/organization/94669.pdf

Are the International Driving Permits issued in your home country in written English? Do they look like an impressive piece of ID, or like a dull child's art project? They're not on TSA's list, but my guess is that a lot of TSA folks would look at one of the better ones and say, "It's kinda like a driver's license, and it's kinda like a passport, and we take both of those, so I'll take it."

http://en.wikipedia.org/wiki/Interna...Driving_Permit