Thanks for the responses. I realized after I posted the question that some would be wondering what it was. Thanks to those who answered! I'll keep my eyes open. I'd actually love the price savings a plastic one would bring. I have the locking mechanism from my bike rack.
I tend to like to find obscure things to buy such as this. My favorite souvenir last year was a nylon reusable shopping bag that folds up into a pouch I clip onto my purse. It is green with Mickey printed all over it, and it was only $5.95. Cheap and environmentally friendly, gotta love it! (I found it at the store across from Soarin' , in case anyone is wondering.)