[Brian_K_White]

Not even difficult. They can and do make buttons, headphone and usb jacks, and even mics and speakers. Battery contacts are nothing at all.

[microtonal]

Example: many GPSr units have replaceable AA batteries and support IPX7. It's not exactly rocket science -- a good locking mechanism and a rubber seal.

[lb1lf]

The GPSr crowd tend to be less obsessed by their devices being a fraction of a millimeter thinner than last year's model, though.

(Much as I love a good locking mechanism and a rubber seal, I can see it making the phone a little thicker than it would be was the battery non-removable.)

[witheld]

A law requiring everyone to have replaceable batteries puts everyone on even ground- phones will continue to be exactly as thin as they can be.