My dream board or PCB would be a single piece with arduino, dual motor driver and bluetooth class 2 or 3, to embed with the lowest cost as possible.
I was thinking to solder arduino micro 5v, a motor driver chip and the bluetooth chip HC-05 on a perforated board, but i don't know what motor driver chip to solder.
The motor driver chip need to operate at max at 12v and move a small or medium robot with differential drive. If it works i'd like to replicate it by designing a PCB and making a dozen of that boards:)