Design Specialised Li ion battery Charger

We are an electric bicycle kit supplier and are looking to enhance our existing product by developing a faster charger for our battery packs that charges each of the 12 cells in our battery packs individually to 3.6v. The cells in our battery pack can be charged at 3 Amps as a standard charge or up to 10 Amps as a fast charge. We would like a solution that charges each cell individually at least 3 Amps. Our battery packs are just 12 cells in series with a balancing connector connecting to each cell. There is no BMS, so there is nothing to prevent charging on an individual cell level. Other solutions in the market that charge and balance a 12 cell pack are complicated and charge the whole battery pack while balancing individual cells. We want a solution that is dedicated to our particular battery pack and actually charges each cell individually using the balancing connectors on each battery pack. A simple red/green led indication of when each cell is charged is sufficient. We don't need complex readouts. We want a solution that is just plug and play. We want our solution to be as lightweight and small as possible and which can be manufactured cost effectively (ideally for less than $30 each) in large volumes. (1500 units plus). Unit should operate off both 240V and 120V AC household power. Deliverables for this project are circuit designs, a working prototype for testing and sufficient manufacturing details to allow us to seek accurate quotes from manufacturers. Bidders from any country are welcome as project will be managed by email, skype etc. We will provide more detail to winning bidder including specs of battery cells and ideas about implementation.