I wish someone would build a cheap little Bluetooth only Mobile Phone that would only work when connected to your smartphone just like ear buds work, to make it easier to make calls in the sun or places where you don't want to take your good phone.
It would look like a simple cellphone, like we had before smartphones, with buttons to dial, and a small display but it would be Bluetooth only so it would only work using the 3G plan on your Smartphone or Tablet just like your Bluetooth ear-bud does.
This device would allow you to make calls in bright sunlight or while your phone or tablet is charging. If your out on a boat or your doing something that may damage your smartphone, you set your smartphone someplace safe within 30 feet and use the Bluetooth phone.
So if you build cellphones or Bluetooth ear-buds please take this idea and build one. If you already built it, please point me to your site.