The sleves and cases from Fotoparadies (affiliated to dm.de) have already been mentioned.
The summary for the moment: They offer a sleeve for FP2, FP3, FP4 and FP5 that can be printed with an image. The available colours are black and white. They use vegan leather and microfibre.
For the FP5 they also offer a printed silicon case and a case with a chain. The colors and materials vary and partly they offer leather.
If you fetch the product from a local DM store you can save the P&P. The prices range from about 20€ to 35€.
This offer seems to be available to germany, I don’t know, if it is available to other countries.