The feasibility of using commercial CMOS processes for implementing scalable cryogenic control electronics for universal quantum computers is investigated. Using a systems engineering approach, we break the system down into sub-systems and model the individual components down to transistor level. First results for area demand and power consumption indicate that even with a standard CMOS process, it should be possible to operate hundreds of qubits. Using dedicated low power processes with reduced supply voltage, this number could be further increased in the long term by four or more orders of magnitude, allowing the control of millions of qubits.