The best solution would involve a grip/mount for the phone that allows standard SLR lenses to be mounted as well...
Several here are waiting for BeastGrip to come to market... Do a web search for "cell phone camera lens mount" and similar terms.
cell phone camera lens mount - Bing
I'm interested in finding a grip type mount myself, but have not been in a particular hurry. It should probably have a trigger for the camera button, a hot shoe, a trip[od mount and a lens mount. I'm sure it will cost me quite a bit... I'd also like a wide range of reach for accommodating different cell phones as I have a 1520.