Since such a device has a very big chance to be used mostly from home, it may be also an option to also offer the (additional) option of using the device in a plugged-in manner and draw power either from an USB, either from a charger. It may also mean some more accessories to be sold.

Another direction could be bigger/better known rechargeable batteries - like Nokia's BL5C or Sony's NP-BX1 (I'm talking about size, not about the voltage, that's something I'm not good at).
I am telling this because some years ago I've had a camera using AA batteries (luckily also rechargeable) and at start I was extremely happy that it works with standard batteries I've soon got disappointed that I had to carry with me a huge lot of them if I wanted to make pictures for one full day. My later camera works with NP-BX1, I have 3 such batteries (one original, 2 cheaper Chinese ones) and I usually don't need 2 for one full day. Plus a cheap Chinese external charger working from USB and the batteries' small format makes a happy family. Indeed, I cannot buy the batteries at the next shop, but I can recharge mine in the car.