Nanoscale FinFET devices are emerging as the transistor of choice in 32nm CMOS technologies and beyond. This is due to their more effective channel control, higher ON/OFF current ratios, and lower energy consumption. This paper presents an efficient current source model (CSM) for FinFET devices operating in the near/sub-threshold regime, considering multiple input switching (MIS) and accounting for the effect of internal node voltages of the logic cell. The main problem of the traditional MIS model is that it requires high-dimensional lookup tables. In this paper, we combine non-linear analytical models and low-dimensional CSM lookup tables to simultaneously achieve high modeling accuracy and time/space efficiency. The proposed framework is verified by experimental results on the 32nm Predictive Technology Model for FinFET devices.