[idea help]bluetooth|Wifi|armband w/screen

I have been interested in making a type of armband, for years now.

What I want:
Compatibility: Android

Bluetooth- To tell you who messaged me, or is currently calling, and be able to send texts through bluetooth. (Possibly in the future allow it to accept phone calls)
Wifi capabilities- So I can connect to the internet and use email, or IM. *Even if I have to make applications, OS, and do SDK's I'm willing to learn.
*Anything else can be programmed in later*
*No I don't want to put a phone into the armband and call it a day.*

However, I don't know where to start. I know I will need to know about OS's and probably make, or modify an OS.
I will need a touch screen (3.5 roughly), some sort of processor, Bluetooth adapter, and wireless adapter, a battery *removable preferred*, and sd card.. but I don't know anything else. Nor where to find the hardware.
I will also need to know how to program the hardware to function with the software.

I know some programming *still beginner*.
I have some basic experience in c++, java, html, and css. and arduino
I have an Arduino.
I am asking for where to start. I have an Arduino. I've heard things about raspberry pi, and it might work? I don't know of anything else.. nor if it either will..

*Due to wanting compatibility with android would I have to have it android OS too? Does it have to be android? Can it be just linux build? or what..

Any pointers, links to guides, and hardware/software to help me start would be a great help and much appreciated.

**Sorry if this isn't in the right forum.. I'm very new and I wanted to ask some people who are in the tech field their thoughts..