I came across Vaja Cases (
site) when I was looking for website design ideas and immediately fell in love with their iPod designs.
Two months later I've bought an X30 and decided to order their DE42 case. I bought the personalised version, in a light grey colour (see picture), although it actually turned out to be more of a stone colour. There is a disclaimer about leather colour variances, but I like this colour just as much, so wont try complaining.
It's beautifully hand-crafted and the leather is gorgeous. It's sturdy enough yet soft and supple.
You can smell the leather and can almost feel the work that went into it.
Under the cover it has a money slot (for notes I presume) and two SD card slots.
Overall, it was a lot of money ($100) but well worth it. It's retro-looking yet stylish and superbly well-made. Turns my X30 into a fashion icon (just like their cases have done to the iPod).