Looking for a quick solution to mount my iPhone 4 on my tripod I decided to make a quick release plate. My tripod came with a quick release plate so I took out my digital callipers and made several measurements. A few minutes later in Blender I had come up with the initial design. It is designed to hold the phone in place by friction, it doesn't need to be that sturdy as I don't intend moving the tripod with the phone in place that much.
It printed very well in translucent blue PLA 4043D but the walls on top were a little too thin which meant they drooped a bit. I have since redesigned it to make the walls about twice as thick, Skeinforge should add an infill.
I have included the paper measurements I've taken in case they are of any use to people. It also gives an insight into how I designed it.
Alter the design and print. This was designed for an iPhone 4 in a polycarbonate case and a Velbon DF-40 tripod. I'm not sure how standardised quick release plates are but I guess you will need to modify it to fit your specific tripod.