The recent invention of magnetoresistive bipolar spin-transistors makes possible the creation of new spintronic logic families. Here we propose the first logic family exploiting these spin-transistors, extending emitter-coupled logic (ECL) to achieve a greater range of basis logic functions. By placing the wire from the output stage of ECL logic elements near spin-transistors in other parts of a circuit, additional basis logic elements can be realized. These new logic elements support greater logic minimization, resulting in enhanced speed, area, and power characteristics. A novel magnetic shielding structure provides this logic family with the crucial ability to cascade logic stages. This logic family achieves a power-delay product 10 to 25 times smaller than conventional ECL, and can therefore be exploited to increase the performance of very high-speed circuits while broadening the range of design choices for a variety of electronic applications.