Actually, there are ways of using full size pro lenses with the iPhone, See this article and video clip about a filmmaker who used an iPhone to make a full length feature film: "Uneasy Lies the Mind". He used an iPhone adapter that enables the use of professional full size lenses. The video shows him demonstrating it:

http://www.dailymail.co.uk/news/article-2572764/Uneasy-Lies-The-Mind-fea...

Only problem might that each iPhone version is a different size and shape and adapters for one might not fit the later versions.