I lost a pair of jeans last year, and after all that time I still marveled that they had never turned up. I was truly mystified.
Last week I was trying to fix my dresser drawer and keep it from catching on the slides (cheap IKEA crap grumble grumble), so I yanked it out, and my long-lost jeans fell from where they'd been wedged onto the floor. They still fit. So I guess the moral of the story is never give up.
Actually, that's terrible advice; it's sometimes best to cut your losses, walk away, and never look back!
Ok, then, the moral of the story really is if you can't find an article of clothing anywhere and you only wore it like twice and know for a fact you never took it off outside your house, check behind your dresser drawers. (I also found three socks and a camisole.)