I have desired to use translucent business cards for clients.  They are usually too much for identity budgets, but when it's possible they make a mark.  Business cards are meant to stay in the pocket and on the desk of the person you give it to.  Setting yourself apart is essential and here is a fun way you can do this.  Hope this gets your design brain moving. 

Here is the designers website http://www.alekchmura.com/