A portable, battery operated, 3"x5" color printer.
I had a friend, who, when he would travel in third world countries, would take polaroids of people to give to them. Many of whom had never had a photo of themselves ever before. I think it would be cool to be able to do that with a digital camera. Something I could put in a backpack, and would beable to take some abuse.
Okay, get to work. I hope to see it on the market by Christmas.
This brings me into another issue with modern digital cameras and world travel. Everywhere I've been, I can buy your standard batteries. But many places the power has been very iffy, or non-existant. This means the people with manufacturer specific rechagables are shit out of luck. I'm serious, in the rain forests in Peru, we would stumble across tiny villages (4 or 5 huts) where they have no power, but they were selling batteries and Coca Cola. It was kind of surreal.
I wish they made some sort of adapters so you could use regular batteries to power newer digital cameras, even if you would burn through the batteries like crazy.