The Volkswagen Up! has a socket on the dashboard to mount the optional "Maps & More" Sat Nav unit. I wanted a simple mount for my mobile phone - in this case the HTC One (in a case). You attach this by flexing the stand until it clips into place and you can angle the phone left/right to suit.
There are two pieces - the stand and the clip. They are secured together with a screw (not supplied!) although you could glue if preferred. You should be able to take the clip file into your preferred 3D package and resize or reshape to fit your own phone model (if you do - please share your hack!)
Both pieces were made almost wholly in Google SketchUp. It took around 4-5 iterations to get the stand to the right size, flexibility and grip to be usable in the dashboard socket. The phone clip was easier is there is greater room for error given the flexibility of this piece. There was a final bit of Boolean work carried out in Cinema4D.