Ive just been introduced to Umbra, a world-wide homewares company with design at its heart. One of the novel ideas that it is currently selling is this card and key holder. Just check out the reviews on it. Whilst most card holders only manage 3 or 4 cards at a time these bad boys can manage much more. So its like carrying around a secure wallet whilst you are out and about.
For more on the company check out http://www.umbra.com/