Progress on 19.11.2012
Bluetooth Headset
It works! It's not ideal, but it'll be there when you need it most.
Old (SCO) and New (A2DP) standards are supported!
Minimum version
Minimum version will be Android 2.2
Phone can be easily upgraded from 2.1 (Eclair) to 2.2 (Froyo), so there is no sense in providing support for less version.
Testing for Android 4.2 (Root)
As Android 4.1, ver. 4.2 will need ROOT access, to work properly.