The Vibe by Shapeways will put your waveform of choice, selected from any track on SoundCloud, on to a custom iPhone case.
'Sound you can touch' is the tag line that Shapeways goes for, turning your favourite waveform in to a black or white 3D printed plastic case.
You'll need a SoundCloud account to get started after which you can search for tracks and sounds and then select your favourite bit to go on the back of your case, sorry, The Vibe.
The US site is currently charging $19.95 for your custom iPhone case, though for now the worldwide shipping charges unfortunately double that if you want it sent to the UK.
Here's hoping for a more UK-friendly solution soon, in the meantime we'll figure out which waveform to choose...