Some of my SecondLife friends started selling game cards in SecondLife for Linden dollars.  I know you can probably find somebody here to exchange bitcoins for lindens, then you could buy the cards from them.  I don't know if they are still doing it.  The project was experimental about a year ago and they keep getting banned from SL for shooting people with penises.  I haven't seen them in a while.  If you want to look them up they are known as Woodbury.