Mobile phone cameras

Mobile phone cameras are getting to the stage where a separate camera is an unnecessary indulgence. But the problem is that they only do straightforward photos. It would be a great product differentiator for phones were they to have the option of additional lenses (fish eye, wide angle, fibre optic, macro, zoom, etc). Give that phones are much smaller than SLRs, a new range of lenses would need to be developed. And as phones should ideally be flat (most of the time), the (normal) lens would need to screw into the phone body - obviously a fibre optic or zoom lens would stick out, but these would only be used on occasion so that wouldn't be an issue.

If the housing was standardised then people would be able to use their old lenses when they got a new phone; on the plus side for the manufacturer, the lenses would be another optional extra to generate more revenue.