Here’s an iPhone 4 case that looks like an old school cassette tape. It even comes with a classic transparent plastic tape case, which can also be used as a stand. I just ordered one! [BUY] (via Strapya World w/ plastic cassette case)
You can also buy some cheaper replicas in additional colors via Amazon (w/o the plastic case).
PURCHASE: Black/Red | Blue/Yellow | Cream/White | Purple/Blue | Pink/Blue | Coffee/Silicone